This page in your language

فارسی

العربية

Deutsch

Español

Français

日本語

한국어

Português

中文

हिन्दी

B1 adjective #8,000 most common 10 min read

もろい

moroi Top 8,000

Practice it Examples Notes & Tips もろい in 30 Seconds

Explanation もろい in your Level:

At the A1 level, you should learn 'moroi' as a basic word for things that break easily. Think of it like 'fragile' on a box. You can use it for simple sentences like 'This glass is fragile' (Kono garasu wa moroi). It's an i-adjective, so it's easy to use at the end of a sentence. At this stage, focus on physical objects you can see and touch. Don't worry about the abstract meanings yet. Just remember that it's a way to describe something that isn't strong and might shatter if you drop it or hit it. It's a useful word to know when you're shopping or handling things in a kitchen. You might also hear it in very simple stories or cartoons when a character's house or toy breaks. Always remember to add 'desu' at the end to be polite: 'Moroi desu.'

For A2 learners, 'moroi' starts to appear in more descriptive contexts. You can use it to describe materials like 'old wood' or 'thin ice.' You also start to learn the negative form 'morokunai' (not fragile) and the past tense 'morokatta' (was fragile). At this level, you might encounter the compound 'namida-moroi,' which means someone who cries easily. This is a very common expression in Japan. You can use it to talk about yourself or your friends in a friendly way. For example, 'I am namida-moroi' means you cry during sad movies. You're moving beyond just physical objects and starting to use the word to describe people's simple emotional traits. It's important to start noticing that 'moroi' is different from 'yowai' (weak), as 'moroi' specifically means things that fall apart easily.

At the B1 level, you are expected to use 'moroi' for more abstract concepts. This includes describing a person's character, a relationship, or a plan. You might say a plan is 'moroi' if it doesn't have a good foundation and will fail easily. You are also learning to use it with particles, like 'shōgeki ni moroi' (fragile against impact) or 'yūwaku ni moroi' (weak against temptation). You should be able to understand the word in news reports or more complex stories. This is the level where you distinguish between 'moroi' and 'kowareyasui.' 'Kowareyasui' is for things that break, while 'moroi' is more about the material or nature of the thing itself. You should also be comfortable using it in various grammatical structures, such as 'moroku naru' (to become fragile).

By B2, 'moroi' should be a natural part of your vocabulary for describing structural and systemic weaknesses. You can use it to discuss social issues, economic foundations, or complex psychological states. You might read about a 'moroi kiban' (fragile foundation) of a government or a company. You understand the nuance that 'moroi' often implies a sudden collapse or crumbling. In literature, you see it used to describe the ephemeral nature of life or beauty. You can use it more flexibly in speech to add nuance, such as 'angai moroi' (surprisingly fragile). You also start to recognize the kanji '脆い' even if you don't write it often. Your understanding of the word now includes its role in expressing 'mono no aware' (the pathos of things) in Japanese culture.

At the C1 level, you have a deep understanding of the literary and technical nuances of 'moroi.' You can compare it with formal synonyms like 'zeijaku' (vulnerability) and know exactly when to use each. You use 'moroi' to describe intricate human emotions and the delicate balance of power in professional or political settings. You might use expressions like 'moroku mo kuzureru' (to crumble all too easily) to describe the fall of an empire or the end of a long-term project. You are sensitive to the poetic connotations of the word and can use it to create specific moods in your writing. You also understand technical uses in specialized fields like materials science or high-level psychology, where 'moroi' describes specific failure modes or personality disorders.

At the C2 level, your mastery of 'moroi' is indistinguishable from a native speaker. You understand its most archaic and rare usages in classical literature as well as its most modern slang or technical applications. You can discuss the etymology of the kanji and how the meaning has evolved over centuries. You use 'moroi' with perfect precision, capturing the exact degree of fragility you wish to convey. You are aware of how the word interacts with other high-level vocabulary to create complex metaphors. Whether you are writing a philosophical essay, a technical report, or a piece of fiction, 'moroi' is a tool you use with absolute control to describe the fundamental instability of the physical and abstract world.

Practice it Examples Notes & Tips

もろい in 30 Seconds

Used for things that shatter or crumble easily.
Commonly describes people who cry easily (namida-moroi).
Applicable to physical materials, emotions, and plans.
Implies a lack of internal strength or resilience.

The Japanese adjective もろい (moroi), often written with the kanji 脆い, is a multifaceted word that English speakers usually translate as 'fragile,' 'brittle,' or 'weak.' However, its nuance goes much deeper than just a physical state. At its core, moroi describes something that lacks the internal strength to withstand pressure, impact, or emotional stress, leading it to crumble or break easily.

Physical Fragility: This refers to materials like thin glass, old wood, or dry crackers that shatter upon contact. For example, 'Kono kabe wa moroi' (This wall is brittle/fragile).
Emotional Vulnerability: One of the most common uses is 'namida-moroi' (涙もろい), describing someone who is easily moved to tears. It suggests a heart that is 'fragile' in the face of sentimentality.
Structural/Abstract Weakness: Used for relationships, foundations, or arguments that lack substance and collapse under scrutiny. A 'moroi kizuna' is a fragile bond between people.

彼は精神的にもろい部分がある。 (Kare wa seishinteki ni moroi bubun ga aru.) - He has a mentally fragile side.

In daily Japanese life, you might hear this word when discussing the quality of a product or the resilience of a person's character. Unlike 'yowai' (weak), which is a general lack of power, moroi implies a specific tendency to fall apart. It is a word that carries a sense of transience and delicacy, often appearing in literature to describe the fleeting nature of beauty or human connections. When you use moroi, you are highlighting the vulnerability of the subject, suggesting that even a small amount of force could cause a significant change in its state.

この古い建物の土台は非常にもろい。 (Kono furui tatemono no dodai wa hijō ni moroi.) - The foundation of this old building is extremely fragile.

Understanding the kanji 脆 is also helpful. The radical on the left represents 'flesh' or 'body' (月/肉), and the right side originally depicted something being cooked or softened. This visualizes the idea of something becoming soft or easily broken down. In modern usage, it extends to abstract concepts like markets, defenses, or even a person's resolve. If a sports team has a 'moroi' defense, they might play well initially but collapse completely after conceding a single goal.

情にもろい。 (Jō ni moroi.) - To be easily moved by emotion/pity.

Context: Materials: Used for glass, ceramic, or brittle metals. It describes the physical property of shattering rather than bending.
Context: Psychology: Describes a lack of mental resilience or a tendency to be overwhelmed by feelings.

彼女の決心は驚くほどもろい。 (Kanojo no kesshin wa odoroku hodo moroi.) - Her determination is surprisingly fragile.

Using もろい (moroi) correctly requires distinguishing between its literal physical meaning and its metaphorical emotional meaning. As an i-adjective, it follows standard grammatical patterns for conjugation. You can use it to modify nouns directly or as a predicate to describe a subject.

Direct Modification: Place it before a noun: 'Moroi garasu' (Fragile glass). This emphasizes the inherent quality of the object.
Predicate Usage: Ending a sentence: 'Kono kabe wa moroi desu' (This wall is fragile). This is common in descriptive speech.

衝撃にもろいので、注意してください。 (Shōgeki ni moroi node, chūi shite kudasai.) - It is fragile against impact, so please be careful.

When discussing people, 'moroi' is often paired with particles like 'ni' to show what they are vulnerable to. 'Yūwaku ni moroi' (vulnerable to temptation) or 'jō ni moroi' (easily moved by pity) are classic examples. It describes a character trait where one gives in easily. In a business context, it might describe a strategy or a market position that lacks stability.

彼の主張は論理的にもろい。 (Kare no shujō wa ronriteki ni moroi.) - His argument is logically weak/fragile.

In literary contexts, you might see 'moroku mo kuzuresaru' (to crumble away fragrantly/easily). This emphasizes the suddenness and total nature of the collapse. Whether it's a sandcastle, a dream, or a political regime, 'moroi' captures that moment where structural integrity fails completely. It is a very evocative word that appeals to the senses, making the listener imagine the sound of something snapping or the sight of dust falling.

友情なんて、案外もろいものだ。 (Yūjō nante, angai moroi mono da.) - Friendship is surprisingly fragile.

Compound: Namida-moroi: Meaning 'prone to tears.' Used affectionately or self-deprecatingly for someone who cries at movies or weddings.
Compound: Moroku mo: Meaning 'easily' or 'all too easily.' Often used before verbs of destruction like 'kuzureru' (to collapse).

そのプラスチックは日光に当たるともろくなる。 (Sono purasuchikku wa nikkō ni ataru to moroku naru.) - That plastic becomes brittle when exposed to sunlight.

You will encounter もろい (moroi) in a wide variety of settings, ranging from hardware stores to emotional heart-to-hearts in dramas. Its versatility makes it a staple of the Japanese language. In a practical sense, you'll see it on warning labels for fragile items, though 'kowaremono' is more common for shipping. In technical fields like engineering or geology, 'moroi' describes the physical properties of rock or metal that might fail under stress.

Anime and Manga: Characters often use 'moroi' to mock an opponent's defense or resolve. 'Kisama no tate wa moroi!' (Your shield is brittle!). It's also used in romantic scenes to describe a character's hidden vulnerability.
News and Finance: Commentators might describe a 'moroi keizai kiban' (fragile economic foundation) or how a market is 'moroi' in the face of sudden bad news.

あいつは見かけによらず、涙もろいんだ。 (Aitsu wa mikake ni yorazu, namida-moroi nda.) - Despite his looks, he's a real softie (easily moved to tears).

In everyday conversation, 'namida-moroi' is perhaps the most frequent variant. If you cry at a commercial or a sad story, a friend might say, 'Namida-moroi ne!' This isn't usually an insult; it's an observation of your empathetic nature. You'll also hear it when people talk about old infrastructure. After an earthquake, news reports often mention 'moroi tatemono' (fragile buildings) that are at risk of collapse.

この素材は熱にもろい性質がある。 (Kono sozai wa netsu ni moroi seishitsu ga aru.) - This material has a property of being brittle under heat.

In Japanese literature (bungaku), 'moroi' is used to create a mood of 'mono no aware'—the pathos of things. Writers use it to describe the fleeting life of a cherry blossom or the fragile peace between two warring factions. It evokes a sense of sadness that something beautiful is so easily destroyed. When you hear this word in a song lyric, it often refers to a 'moroi kokoro' (fragile heart) that has been broken by love.

Daily Life: Talking about cheap toys, old furniture, or a poorly made shelf. 'Kono tana, morosō da ne' (This shelf looks fragile, doesn't it?).
Self-Reflection: People use it to describe their own weaknesses. 'Watashi wa yūwaku ni moroi node...' (Since I'm weak against temptation...).

While もろい (moroi) is a common word, learners often confuse it with other adjectives that mean 'weak' or 'fragile.' The most common error is using it as a direct synonym for yowai (weak). While all moroi things are in some sense yowai, not all yowai things are moroi.

Moroi vs. Yowai: 'Yowai' is a general lack of strength (a weak light, a weak person). 'Moroi' specifically implies crumbling or breaking easily. A person can be 'yowai' (not strong) without being 'moroi' (prone to breaking down emotionally).
Moroi vs. Kowareyasui: 'Kowareyasui' means 'easy to break.' This is more functional. 'Moroi' is more about the material quality or the inherent nature. You'd say a smartphone is 'kowareyasui,' but you'd say the glass it's made of is 'moroi.'

× 彼は体がもろい。 (Incorrect for physical health)
○ 彼は体が弱い。 (He has a weak body/constitution.)

Another mistake is using 'moroi' to describe physical health or illness. If someone gets sick easily, you should use 'karada ga yowai' or 'byōkigachi.' 'Moroi' would sound like their bones are physically brittle (which is a specific medical condition, not a general state of health). Similarly, for 'weak' coffee or 'weak' light, 'moroi' is never used; 'usui' or 'yowai' are the correct choices.

Learners also sometimes forget the 'namida-moroi' compound and try to say 'namida ga yowai' or 'sugu naku.' While 'sugu naku' (cries easily) is correct, 'namida-moroi' is the idiomatic way to describe that personality trait. Finally, be careful with the kanji. While usually written in kana, the kanji 脆 is N1 level, so don't feel pressured to use it in basic writing, but recognize it when reading.

× このお茶はもろい。 (Incorrect for weak tea)
○ このお茶は薄い。 (This tea is weak/thin.)

Register Errors: Using 'moroi' in a highly technical report where 'zeijaku' (vulnerable/weak) might be more appropriate for systems or security.

To truly master もろい (moroi), you should understand how it compares to its synonyms. Depending on the context, one of these might be a better fit.

脆弱 (Zeijaku): This is a more formal, academic, or technical term for 'fragile' or 'vulnerable.' You'll see it in 'security vulnerabilities' (sekyuriti no zeijakusei) or describing a weak social structure. It sounds more clinical than 'moroi.'
壊れやすい (Kowareyasui): Literally 'easy to break.' This is the most common word for fragile objects in daily life, like a vase or a toy. It's functional and straightforward.
弱い (Yowai): The general word for 'weak.' Use this for physical strength, weak signals, or people who aren't good at something.
デリケート (Derikēto): From the English 'delicate.' Used for skin types, sensitive issues, or refined machinery. It often has a more positive or neutral nuance than 'moroi.'

システムの脆弱性を修正する。 (Shisutemu no zeijakusei o shūsei suru.) - Fix the system's vulnerability.

When choosing between these, consider the 'vibe.' If you want to sound poetic or describe an inherent structural flaw that causes crumbling, 'moroi' is perfect. If you are talking about a computer bug, 'zeijaku' is the way to go. If you are warning someone not to drop a glass, 'kowareyasui' is the most natural. Understanding these subtle shifts will make your Japanese sound much more native and precise.

この問題は非常にデリケートだ。 (Kono mondai wa hijō ni derikēto da.) - This issue is very delicate/sensitive.

In summary, moroi is the go-to word for anything that crumbles, whether it's a physical material, an emotional state, or an abstract concept like a plan or a bond. By mastering its various forms and compounds like 'namida-moroi,' you gain a powerful tool for expressing vulnerability and fragility in Japanese.

How Formal Is It?

Fun Fact

The kanji '脆' is actually a combination of the 'flesh/body' radical and a phonetic component that also implies 'softening.' It suggests something that has lost its firmness.

Pronunciation Guide

UK mo-ro-i

US mo-ro-i

Flat pitch accent (Heiban), meaning the pitch stays relatively level after the first syllable.

Rhymes With

Shiroi (White) Kuroi (Black) Hiroi (Wide) Noroi (Slow) Soroi (Set/Uniform) Toroi (Dull/Slow) Horoi (Slightly drunk - often used as horoyoi) Oroi (Rarely used, but phonetically possible)

Common Errors

Pronouncing 'r' like the English 'r' (keep it light and flicked).
Elongating the 'o' sounds (keep them short).
Confusing with 'morau' (to receive).
Stressing the wrong syllable.
Not pronouncing the final 'i' clearly.

Difficulty Rating

Reading 3/5

The word is common in kana, but the kanji is N1 level.

Writing 4/5

Writing the kanji 脆 is difficult for intermediate learners.

Speaking 2/5

Simple pronunciation and standard i-adjective conjugation.

Listening 2/5

Distinct sound, though can be confused with other 'm' words.

What to Learn Next

Prerequisites

弱い (yowai) 壊れる (kowareru) ガラス (garasu) 涙 (namida)

Learn Next

脆弱 (zeijaku) はかない (hakanai) 崩れる (kuzureru) 頑丈 (ganjō)

Advanced

脆性 (zeisei) 瓦解 (gakai) 砂上の楼閣 (sajō no rōkaku)

Grammar to Know

I-adjective conjugation

もろい -> もろくない -> もろかった

Compound adjectives

Noun + Moroi (e.g., Namida-moroi)

Adverbial form

Moroku + Verb (e.g., Moroku naru)

Te-form for reasons

Morokute kowai (It's fragile and scary)

Noun form with -sa

Morosa (fragility)

Examples by Level

このカップはもろいです。

This cup is fragile.

Simple predicate usage with 'desu'.

そのおもちゃはもろい。気を付けて。

That toy is fragile. Be careful.

Informal usage of 'moroi'.

もろいガラスですね。

It's fragile glass, isn't it?

Direct modification of the noun 'garasu'.

このかべはとてももろい。

This wall is very brittle.

Adverb 'totemo' modifying 'moroi'.

もろい物は箱に入れてください。

Please put fragile things in the box.

Using 'moroi mono' (fragile things) as an object.

このクッキーはもろいから、すぐ割れる。

These cookies are brittle, so they break easily.

Using 'kara' to show reason.

それはもろくないですよ。

That is not fragile, you know.

Negative form 'morokunai'.

もろい椅子に座らないで。

Don't sit on the fragile chair.

Negative command with 'naide'.

私は涙もろいので、この映画は見られません。

I cry easily, so I can't watch this movie.

Introduction of the compound 'namida-moroi'.

古い家は地震にもろい。

Old houses are weak against earthquakes.

Using 'ni' to indicate the cause of the break.

このプラスチックは寒さにもろい。

This plastic is brittle in the cold.

Contextual fragility (temperature).

昔の服は生地がもろかった。

The fabric of old clothes was fragile.

Past tense 'morokatta'.

もろい素材を使わないでください。

Please do not use fragile materials.

Noun 'sozai' (material) modified by 'moroi'.

彼は見かけによらず、涙もろい人だ。

He is someone who cries easily, despite his appearance.

Phrase 'mikake ni yorazu' (despite looks).

卵の殻は非常にもろい。

Eggshells are extremely fragile.

Formal adverb 'hijō ni' (extremely).

この紐はもろくて使えない。

This string is fragile and can't be used.

Te-form 'morokute' for connecting clauses.

二人の絆は、意外ともろかった。

The bond between the two was surprisingly fragile.

Abstract usage for relationships.

彼は誘惑にもろい性格だ。

He has a personality that is weak against temptation.

Describing character traits with 'ni moroi'.

その計画は土台からしてもろい。

That plan is fragile from its very foundation.

Metaphorical use for 'foundation' (dodai).

日光を浴びすぎると、髪がもろくなる。

If it gets too much sun, hair becomes brittle.

Verb 'naru' (to become) with 'moroku'.

情にもろい彼は、頼まれると断れない。

Being soft-hearted, he can't say no when asked.

Phrase 'jō ni moroi' (soft-hearted).

経済の基盤がもろいことが判明した。

It became clear that the economic foundation was fragile.

Formal noun 'kiban' (foundation/basis).

もろい勝利に酔いしれてはいけない。

One must not be intoxicated by a fragile victory.

Abstract noun 'shōri' (victory).

この接着剤は熱に少しもろい。

This adhesive is a bit weak against heat.

Adverb 'sukoshi' (a bit).

平和な日常は、案外もろいものだ。

Peaceful daily life is a surprisingly fragile thing.

Philosophical observation.

彼の理論は、一つの反論でもろくも崩れ去った。

His theory crumbled all too easily with a single counterargument.

Idiomatic 'moroku mo kuzuresaru'.

精神的にもろい時期は誰にでもある。

Everyone has periods when they are mentally fragile.

Psychological context.

その政権の支持基盤は極めてもろい。

The support base of that administration is extremely fragile.

Political context with 'kiwamete' (extremely).

伝統がもろくも失われていくのを嘆く。

I lament that traditions are being lost so easily.

Lamenting cultural loss.

ガラス細工は美しく、そしてもろい。

Glasswork is beautiful, and fragile.

Juxtaposition of beauty and fragility.

脆い地盤の上に家を建ててはいけない。

You must not build a house on fragile ground.

Physical geology context with kanji.

彼の決心は、彼女の一言でもろくも砕けた。

His determination was easily shattered by her one word.

Shuttering of determination.

文明の虚飾は、自然の猛威の前にもろくも剥がれ落ちた。

The ostentation of civilization was easily stripped away before the fury of nature.

Literary and metaphorical.

彼は、自己の脆さを隠すために虚勢を張っている。

He puts on a brave front to hide his own fragility.

Noun form 'morosa' (fragility).

その条約は、各国の利害関係によってもろくも反故にされた。

The treaty was easily discarded due to the conflicting interests of each country.

High-level diplomatic context.

万物の霊長を自負する人間も、ウイルス一つにもろい存在だ。

Humans, who pride themselves as the lords of creation, are fragile beings in the face of a single virus.

Philosophical/Scientific commentary.

脆い精神を鍛え直す必要がある。

It is necessary to retrain a fragile spirit.

Self-improvement context.

経済のグローバル化は、供給網の脆さを浮き彫りにした。

The globalization of the economy highlighted the fragility of supply chains.

Economic analysis.

彼女の繊細な感性は、時として脆さに通じる。

Her delicate sensitivity sometimes leads to fragility.

Nuanced personality analysis.

脆い記憶を辿りながら、彼は真実を語り始めた。

Tracing back fragile memories, he began to tell the truth.

Abstract usage for memory.

権威の虚像は、民衆の怒りの前にもろくも瓦解した。

The false image of authority crumbled easily before the anger of the people.

Advanced vocabulary like 'gakai' (collapse).

生命の灯火は、かくも脆く、かくも尊いものか。

Is the flame of life so fragile, yet so precious?

Poetic/Archaic style using 'kaku mo'.

脆い均衡の上に成り立つ国際秩序を憂慮する。

I am concerned about the international order that exists on a fragile balance.

Geopolitical analysis.

言語という脆い器に、あふれんばかりの情念を込める。

Pouring overflowing passion into the fragile vessel of language.

Metaphorical use for language.

砂上の楼閣のごとく、その成功は脆い土台の上に築かれていた。

Like a castle in the sand, that success was built on a fragile foundation.

Idiom 'sajō no rōkaku' (castle in the sand).

精神の脆さを克服することこそが、真の強さへの道である。

Overcoming the fragility of the spirit is the very path to true strength.

Philosophical discourse.

脆い夢想に耽る時間は、もう終わったのだ。

The time for indulging in fragile daydreams is already over.

Abstract usage for dreams.

その古文書は、空気に触れただけでもろくも崩れ落ちるほどだった。

The ancient manuscript was so fragile it would crumble just by touching the air.

Extreme physical fragility.

Common Collocations

涙もろい

脆い地盤

衝撃にもろい

情にもろい

脆い絆

脆い素材

脆い精神

脆い土台

熱にもろい

脆くも崩れる

Common Phrases

脆いものだ

— It is a fragile thing. Often used for life or peace.

人生なんて脆いものだ。

脆さを見せる

— To show vulnerability or weakness.

彼は時折、脆さを見せる。

脆い部分がある

— To have a fragile side/part.

誰にでも脆い部分がある。

脆くなる

— To become fragile/brittle.

古くなると脆くなる。

脆い理論

— A weak or fragile theory.

それは脆い理論だ。

脆い勝利

— A fragile or narrow victory.

脆い勝利に終わった。

脆い壁

— A brittle or weak wall.

脆い壁を壊す。

脆い約束

— A fragile or unreliable promise.

脆い約束を交わす。

脆い立場

— A fragile or precarious position.

脆い立場に追い込まれる。

脆い心

— A fragile heart/mind.

脆い心を守る。

Often Confused With

もろい vs 弱い (yowai)

Yowai is general weakness; Moroi is specifically about crumbling or shattering.

もろい vs 壊れやすい (kowareyasui)

Kowareyasui is 'easy to break' (functional); Moroi is 'fragile' (inherent quality).

もろい vs 薄い (usui)

Usui is 'thin' or 'weak' (for liquids/colors); Moroi is never used for liquid strength.

Idioms & Expressions

"涙もろい"

— Easily moved to tears. Very common idiom for soft-hearted people.

母は涙もろい。

Informal

"脆くも崩れ去る"

— To crumble away all too easily. Used for plans or dreams.

野望は脆くも崩れ去った。

Literary

"情にもろい"

— Soft-hearted; easily swayed by emotion or sympathy.

彼は情にもろいのが欠点だ。

Neutral

"砂上の楼閣"

— A castle in the sand; something built on a fragile foundation.

彼の計画は砂上の楼閣だ。

Formal

"脆い地盤"

— Weak foundation; often used metaphorically for business or politics.

脆い地盤の上での経営。

Business

"脆い牙城"

— A fragile stronghold; a position of power that is easily toppled.

牙城は脆くも落ちた。

Literary

"脆い防衛線"

— A fragile line of defense.

防衛線はもろかった。

Military

"脆い平和"

— A fragile peace.

脆い平和が続いている。

Political

"脆い記憶"

— Fading or unreliable memories.

脆い記憶を頼りに書く。

Literary

"脆い決意"

— Weak determination.

彼の脆い決意はすぐ揺らいだ。

Neutral

Easily Confused

もろい vs 脆い (moroi)

Sounds like 'marui' (round).

Moroi means fragile; Marui means round. Context is usually very different.

もろいガラス vs まるいボール

もろい vs 脆い (moroi)

Often confused with 'yowai' by learners.

Moroi implies structural failure/shattering. Yowai is just lack of power.

精神がもろい (fragile spirit) vs 腕力が弱い (weak arm strength)

もろい vs 脆い (moroi)

Similar to 'zeijaku'.

Zeijaku is formal/technical (security/society). Moroi is general/emotional.

脆弱なシステム vs もろいクッキー

もろい vs 脆い (moroi)

Confused with 'hakanai'.

Hakanai is ephemeral/fleeting (beauty/dreams). Moroi is physically or mentally breakable.

はかない恋 vs もろい壁

もろい vs 脆い (moroi)

Confused with 'noroi' (slow).

One letter difference. Moroi is fragile; Noroi is slow.

もろい椅子 vs 足がのろい

Sentence Patterns

[Noun] はもろいです。

このガラスはもろいです。

[Noun] は [Noun] にもろい。

この家は地震にもろい。

[Person] は涙もろい。

田中さんは涙もろい。

もろい [Noun] を [Verb]。

もろい壁を直す。

案外もろいものだ。

友情は案外もろいものだ。

もろくも [Verb]。

計画がもろくも崩れた。

[Noun] の脆さを [Verb]。

精神の脆さを克服する。

かくも脆い [Noun]。

かくも脆い命。

Word Family

Nouns

脆さ (morosa) Fragility; brittleness.

Adjectives

涙もろい (namida-moroi) Prone to tears.

情にもろい (jō-ni-moroi) Soft-hearted.

壊れる (kowareru) - to break

崩れる (kuzureru) - to crumble

脆性 (zeisei) - brittleness (technical term)

弱い (yowai) - weak

脆化 (zeika) - embrittlement

How to Use It

frequency

Common in daily life and literature.

Common Mistakes

Using 'moroi' for weak coffee. → Kono kōhī wa usui.
'Moroi' is for physical or emotional fragility, not concentration of liquids.
Saying 'namida ga moroi'. → Namida-moroi.
It's a compound adjective, so the 'ga' is not needed between 'namida' and 'moroi'.
Using 'moroi' for a person with a cold. → Karada ga yowai.
'Moroi' doesn't refer to general health or immunity.
Confusing 'moroi' with 'marui'. → Moroi (fragile) vs Marui (round).
These are phonetically similar but have completely different meanings.
Using 'moroi' for a 'weak' light or signal. → Yowai hikari / Yowai shingō.
'Moroi' is for things that can break physically or structurally.

Tips

The Cracker Rule

If it acts like a dry cracker—shattering when pressed—it's 'moroi'.

Emotional Softness

Use 'namida-moroi' to describe someone who cries at movies; it's a very native-like expression.

I-Adjective Basics

Remember to conjugate it like 'morokunai' for negatives. Don't use 'da' after it directly.

Construction

In earthquake-prone Japan, 'moroi' is often used to discuss building safety.

Formal Alternative

Switch to 'zeijaku' (脆弱) in academic or technical reports for 'vulnerability'.

Embrace Fragility

Understand that 'morosa' can sometimes be seen as a poetic or beautiful quality in Japan.

Pitch Check

Keep your voice level. 'Mo-ro-i' has a flat pitch accent.

Kanji Recognition

Look for the 'flesh' radical on the left of 脆 to remember it relates to bodies/materials.

Moroi vs Yowai

Always ask: Does it crumble? If yes, use 'moroi'. If it just lacks power, use 'yowai'.

Compound Power

Mastering 'namida-moroi' and 'jō-ni-moroi' will greatly improve your character descriptions.

Memorize It

Mnemonic

Think of 'MOre ROck I' (More Rock, I need!) because the current rocks are too MOROI (fragile) and keep crumbling.

Visual Association

Imagine a cracker (moroi) shattering into many pieces when you touch it.

Word Web

Glass Crying Crumbling Weak Foundation Brittle Namida-moroi Shatter Vulnerable

Challenge

Try to find three things in your room that are 'moroi' and say them out loud in Japanese.

Word Origin

The word 'moroi' is an indigenous Japanese word (yamato-kotoba). It has been used since ancient times to describe things that are not solid or durable.

Original meaning: Easily falling apart or crumbling.

Japonic

Cultural Context

Be careful when calling someone's personality 'moroi' as it can imply they are mentally weak, unless you use 'namida-moroi' or 'jō-ni-moroi' which are softer.

In English, 'fragile' can be negative, but in Japanese, 'moroi' (especially namida-moroi) can be a positive, empathetic trait.

Namida-moroi characters in 'Otoko wa Tsurai yo' (Tora-san). The use of 'moroi' in classic Japanese poetry (Waka). Technical 'moroi' descriptions in earthquake safety manuals.

Practice in Real Life

Real-World Contexts

Physical Materials

もろいガラス
もろい壁
衝撃にもろい
熱にもろい

Personality

涙もろい
情にもろい
誘惑にもろい
精神的にもろい

Abstract Concepts

もろい計画
もろい絆
もろい平和
もろい基盤

Natural Disasters

地盤がもろい
建物がもろい
地震にもろい
崩れやすい

Business/Politics

支持がもろい
経済がもろい
戦略がもろい
脆さを見せる

Conversation Starters

"あなたは涙もろいほうですか？ (Are you the type who cries easily?)"

"この素材は衝撃にもろいので注意してください。 (Please be careful as this material is fragile against impact.)"

"最近のスマホは画面がもろいと思いませんか？ (Don't you think modern smartphone screens are fragile?)"

"彼は情にもろいから、頼み事をしやすいです。 (Since he is soft-hearted, it's easy to ask him for favors.)"

"この古い橋はもろそうで怖いですね。 (This old bridge looks fragile and scary, doesn't it?)"

Journal Prompts

自分が「涙もろい」と感じた瞬間について書いてください。 (Write about a moment when you felt you were 'prone to tears'.)

「もろい絆」を強くするためには何が必要だと思いますか？ (What do you think is necessary to strengthen a 'fragile bond'?)

あなたが持っている物の中で、一番もろい物は何ですか？ (What is the most fragile thing you own?)

精神的にもろくなった時、どうやって立ち直りますか？ (When you become mentally fragile, how do you recover?)

「砂上の楼閣」のような計画を立てたことがありますか？ (Have you ever made a plan that was like a 'castle in the sand'?)

Frequently Asked Questions

10 questions

No, for weak coffee or tea, use 'usui' (thin). 'Moroi' is only for things that crumble or break.

Usually no. It's often used affectionately to mean someone is empathetic or soft-hearted, though in a professional setting it might imply a lack of composure.

'Kowareyasui' focuses on the result (it breaks easily), while 'moroi' focuses on the material or structural quality (it is brittle/fragile).

It is written as 脆い. However, it is very common to see it written in hiragana as もろい.

You would usually use 'yowai.' 'Moroi' would only be used if they 'crumbled' instantly after one hit.

It means someone is easily swayed by their emotions or by pity for others. They are 'soft-hearted.'

Yes, to describe a 'moroi kiban' (fragile foundation) of a company or a plan that lacks solid logic.

'Ganjō' (sturdy) or 'tsuyoi' (strong) are the most common antonyms.

Yes, for things like crackers or pie crusts that are very brittle and crumbly.

Yes, it is a basic adjective (B1 level) that every Japanese learner should know.