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B1 noun 8 min de leitura

無効

mukou

Pratique Exemplos Notas e dicas 無効 em 30 segundos

Explicação 無効 in your Level:

At the A1 level, you only need to know that 無効 (mukō) means 'No' or 'Bad' in the context of tickets and cards. Imagine you are at a train station. You put your card in the machine, and it makes a loud 'beep' and shows red light. The screen might say '無効.' This simply means your card did not work. Maybe it is old, or maybe you don't have enough money. You can think of it as the opposite of 'OK.' In very simple Japanese, you can say 'Kore wa mukō desu' to mean 'This is not valid.' You will see this word on many signs in Japan, often next to a red 'X'. It is a very important word for survival because it tells you when something is not working or not allowed. Even if you cannot speak much Japanese, recognizing these two kanji (無 and 効) will help you understand why a machine or a coupon is being rejected. Just remember: Mu (无/無) means 'No' and Ko (効) means 'Effect.' No effect! It's that simple at this level.

Cadastre-se grátis para ler a explicação completa

At the A2 level, you can start using 無効 (mukō) in basic sentences. You should understand that it is used for rules and things like deadlines. For example, if you have a coupon that says 'Valid until December 31st,' and today is January 1st, that coupon is mukō. You can say, 'Kigen ga sugita node, muko desu' (Because the deadline passed, it is invalid). You will also see this word on your computer or phone. If a setting is 'Off,' sometimes it is called 'mukō.' You can learn the phrase 'mukō ni suru,' which means 'to turn off' or 'to make invalid.' For example, 'Tsuchi o mukō ni suru' means 'to turn off notifications.' At this level, you should be able to distinguish between 'mukō' (invalid) and 'dame' (bad/no good). While 'dame' is very general, 'mukō' is specifically about rules, tickets, and official things. If you are playing a game and someone breaks a rule, their point might be 'mukō.'

Cadastre-se grátis para ler a explicação completa

At the B1 level, you should be comfortable using 無効 (mukō) in various social and professional contexts. You are expected to understand its role as a noun and a na-adjective. You should know common collocations like 'mukō ni naru' (to become invalid) and 'mukō ni suru' (to invalidate/disable). This is the level where you start to encounter 'mukō' in more complex scenarios, such as legal discussions or business contracts. For instance, if a contract is signed without a proper signature, it is 'mukō.' You should also be aware of the noun 'mukōka' (invalidation/deactivation), which is common in technical Japanese. If you are talking about software, you might say 'Security kinō o mukōka shimashita' (I deactivated the security function). You should also be able to recognize the difference between 'mukō' and 'shikkō' (expiration), though they are often used together. 'Shikkō' is the act of expiring, while 'mukō' is the resulting state of being invalid.

At the B2 level, you should have a nuanced understanding of 無効 (mukō) and be able to use it in formal arguments or written reports. You should understand the legal distinction in Japanese law between 'mukō' (void ab initio) and 'torikeshi' (voidable/cancellable). 'Mukō' implies that the action never had any legal effect to begin with, whereas 'torikeshi' means it was valid until someone decided to cancel it. This distinction is crucial for business and law students. You should also be able to use the word in abstract contexts, such as 'mukō na giron' (an invalid/pointless argument) or 'mukō na doryoku' (though 'muda' is more common here, 'mukō' can be used if the effort was disqualified by a rule). You will also encounter it in political contexts, such as 'mukō-hyō' (invalid ballots) and understand the societal implications of high invalid vote counts. Your ability to use 'mukō' should extend to complex grammar patterns like '...to minashi, mukō to suru' (regarded as ... and rendered invalid).

Cadastre-se grátis para ler a explicação completa

At the C1 level, your mastery of 無効 (mukō) should include its use in highly specialized fields such as jurisprudence, advanced computer science, and formal logic. You should be able to discuss the 'Invalidity of Administrative Acts' (gyōsei kōi no mukō) or the 'Nullity of Marriage' (kon-in no mukō) using precise terminology. You should understand how 'mukō' interacts with other legal concepts like 'teishi' (suspension) or 'shikkō' (loss of rights). In a technical sense, you should be able to explain 'cache invalidation' (kyasshu no mukōka) and why it is a difficult problem in distributed systems. Your vocabulary should also include related formal terms like 'mukō-tō-kakunin-no-sutae' (an action for the confirmation of invalidity). You should be able to read and write formal documents where 'mukō' is used to define the boundaries of authority and validity. At this level, you are not just using the word; you are using it to define the parameters of systems and legal frameworks.

Cadastre-se grátis para ler a explicação completa

At the C2 level, you possess a near-native command of 無効 (mukō), including its historical development and philosophical overtones. You can appreciate the nuances of 'mu' (emptiness/nothingness) as it applies to 'kō' (efficacy) in classical Japanese texts or modern legal theory. You can engage in high-level debates about whether certain laws should be declared 'mukō' based on constitutional grounds (iken-shinsa). You understand the subtle rhetorical use of 'mukō' in literature to describe the futility of human endeavor or the breakdown of social contracts. Your usage is indistinguishable from a highly educated native speaker, whether you are drafting a complex software specification that handles 'edge-case invalidations' or arguing a point in a court of law. You are also aware of rare idioms and archaic uses of the kanji combination that might appear in historical documents or specialized academic papers. You can explain the difference between 'absolute invalidity' (zettaiteki-mukō) and 'relative invalidity' (sotaiteki-mukō) with ease.

Cadastre-se grátis para ler a explicação completa

Pratique Exemplos Notas e dicas

無効 em 30 segundos

Used to describe things that are invalid or void, like tickets, rules, or digital settings.
Commonly paired with 'ni naru' (become invalid) and 'ni suru' (make invalid).
Essential for legal, business, and technical contexts in Japan.
Distinguishable from 'muda' (waste) and 'shikkō' (expiration).

The Japanese word 無効 (むこう - mukō) is a fundamental noun and na-adjective used to describe something that has lost its legal force, effectiveness, or validity. At its core, it combines the kanji 無 (mu), meaning 'nothing' or 'without,' and 効 (kō), meaning 'effect' or 'efficacy.' Therefore, the literal translation is 'without effect.' This word is ubiquitous in Japanese society, appearing in everything from legal documents to digital user interfaces. When a contract is found to have a fundamental flaw, it is declared mukō. When a sports player commits a foul before scoring, the point is rendered mukō. Even in daily life, if you try to use an expired coupon at a convenience store, the clerk might politely explain that the coupon is no longer valid using this term.

Legal Context: In the legal sphere, 無効 refers to an act that is void from the beginning (ab initio). Unlike 'cancellation' (取り消し - torikeshi), which assumes an act was valid until it was stopped, a void act is treated as if it never happened. This is a critical distinction in Japanese civil law.
Digital and UI Context: In software development and technology, you will frequently see 無効にする (to disable/make invalid) and 有効にする (to enable/make valid). For example, a 'disabled button' is often described as being in a 無効 state.

期限が切れているため、このチケットは無効です。
— Because the deadline has passed, this ticket is invalid.

The versatility of 無効 extends to abstract concepts as well. If an argument is based on a false premise, the logic itself might be called mukō. In the realm of sports, specifically in Sumo or Martial Arts, a match can be declared mukō-jiai (no contest) if neither party can be declared a winner or if external factors interfere. Understanding this word is essential for navigating Japanese bureaucracy and technology.

入力されたパスワードは無効な形式です。
— The entered password is in an invalid format.

Medical Efficacy: While 無効 can mean 'ineffective' in a medical sense (e.g., a treatment that doesn't work), Japanese speakers more commonly use 効果がない (kōka ga nai) for medicine. Use 無効 primarily for rules and binary states.

その契約は法律によって無効とされた。
— That contract was rendered void by law.

Using 無効 correctly requires understanding its grammatical flexibility. It functions primarily as a noun, but in practice, it acts like a no-adjective or a na-adjective depending on the sentence structure. The most common patterns involve the verbs になる (ni naru) and にする (ni suru). These phrases allow you to describe something losing its validity or someone actively revoking it.

このクーポンは、他。の割引と併用すると無効になります。
— This coupon becomes invalid if used in conjunction with other discounts.

When you want to say that something is 'invalid' as a state, you use 無効だ (mukō da) or 無効です (mukō desu). If you are modifying a noun directly, such as an 'invalid ticket,' you can say 無効なチケット or sometimes 無効のチケット, though the former is more common in modern usage. In formal writing, particularly in legal or business contexts, you will see it paired with と見なす (to minasu), meaning 'to be regarded as invalid.'

Common Verb Pairings

無効にする: To invalidate / To void (Active action)
無効になる: To become invalid / To expire (Passive change)
無効を宣言する: To declare invalidity
無効を申し立てる: To file a claim for invalidity (Legal)

管理者権限でその設定を無効にしました。
— I disabled that setting using administrator privileges.

In a technical setting, you might encounter 無効化 (mukōka), which means 'invalidation' or 'deactivation.' This is often used as a noun to describe the process of making something ineffective. For example, kinō no mukōka means 'disabling of a function.' This suffix -ka (化) is very productive in Japanese, turning nouns into concepts of 'becoming' or 'making into.'

不正な操作が行われたため、アカウントが一時的に無効化されました。
— Due to unauthorized activity, the account has been temporarily deactivated.

If you spend any time in Japan or interact with Japanese systems, 無効 will become a very familiar sight. It is not just a 'dictionary word'; it is a 'life word.' You will hear it in train stations, see it on websites, and read it in news reports about elections or court cases. Its frequency is particularly high in domains where rules and systems are central.

At the Train Station: If you try to go through a ticket gate with an expired pass, the gate will close and a screen will often flash 「このカードは無効です」 (This card is invalid). Station staff use this word when explaining why a certain ticket cannot be used for a specific express train.
In Politics and News: During elections, you will hear about 無効票 (mukōhyō)—invalid votes. These are ballots that were filled out incorrectly, left blank, or had extra comments written on them, rendering them uncountabe. News anchors will report the number of mukōhyō to show the level of voter error or protest.

選挙管理委員会は、書き込みのある投票を無効票として処理した。
— The election commission processed ballots with writing on them as invalid votes.

In the business world, 無効 is vital for contract negotiations. If a contract is signed by someone without the proper authority, a lawyer will argue that the keiyaku (contract) is mukō. You might also hear it in sports commentary. In soccer, if a goal is scored after the referee blew the whistle for a foul, the commentator will say 「今のは無効です！」 (That one is invalid/doesn't count!).

オフサイドの判定により、ゴールは無効になった。
— Due to an offside call, the goal was invalidated.

Online Shopping: When shopping on Amazon Japan or Rakuten, if you enter a gift card code that has already been used, you will see the error message 「このコードは無効です」. It is the standard way to say a code is incorrect or spent.

While 無効 (mukō) seems straightforward, English speakers often make mistakes by overusing it or confusing it with similar-sounding words. The most common error is the confusion with its homophone 向こう (mukō), which means 'over there' or 'the other side.' While they sound the same, the 'o' in 'over there' is long (mukou), whereas in 'invalid,' it is short (muko) in some dialects but usually long in standard Tokyo Japanese. The real difference lies in the kanji and the context.

Mistake 1: Mukō vs. Muri: Learners sometimes use 無効 when they mean 無理 (muri). 無理 means 'impossible' or 'too much.' For example, if you can't enter a room, don't say 'The door is mukō.' Say the door is locked or it's muri to enter. 無効 only refers to the validity of a rule or status.
Mistake 2: Mukō vs. Muda: Another common confusion is with 無駄 (muda), which means 'waste' or 'useless.' If you do something that doesn't produce results, it is muda. If you do something that doesn't count because it broke a rule, it is mukō. For instance, 'studying for a test that was canceled' is muda, but 'a test answer written after the time limit' is mukō.

❌ 彼の努力は無効だった。
✅ 彼の努力は無駄だった。
— His effort was a waste (muda), not 'invalid' (mukō).

In writing, the kanji 効 (effect) is often confused with 功 (merit/success). Both are pronounced 'kō.' However, 無功 is not a standard word. Always ensure you are using the 'effect' kanji which features the 'power' (力) radical on the right side.

❌ この免許は取消です。
✅ この免許は無効です。
— While 'torikeshi' (cancellation) is used, for a license that has just expired or is not valid, 'mukō' is more common to describe its state.

To truly master 無効, you need to know how it compares to its cousins in the 'lack of effect' family. Japanese has several words that overlap with 'invalid,' each with a specific flavor and domain of use.

無効 (Mukō) vs. 失効 (Shikkō): 失効 specifically means 'to lose effect' or 'to expire.' While mukō describes the state of being invalid, shikkō describes the process of the validity running out. For example, a passport shikkō (expires) after 10 years, and then it is in a mukō (invalid) state.
無効 (Mukō) vs. 取消 (Torikeshi): 取消 means 'cancellation' or 'revocation.' In law, mukō means something was never valid to begin with, whereas torikeshi means something was valid but has been made invalid from a certain point onward because of a specific action.
無効 (Mukō) vs. 無用 (Muyō): 無用 means 'useless' or 'unnecessary.' It is often used in signs like 「天地無用」 (Tenchi Muyō - Do not overturn/This side up) or 「他言無用」 (Tagon Muyō - Don't tell others). It doesn't mean something is 'invalid' by a rule, but rather that it is 'forbidden' or 'not needed.'

免許証が失効したので、運転はできません。
— My license has expired (shikkō), so I cannot drive.

Finally, we have 無力 (muryoku), which means 'powerless' or 'helpless.' This is used for people or organizations, not for tickets or contracts. If you feel like you can't do anything to stop a disaster, you are muryoku. If your ticket doesn't work, it is mukō.

このボタンを無効化してください。
— Please deactivate/disable this button.

How Formal Is It?

Curiosidade

The kanji for 'Mu' (無) is one of the most famous in Zen Buddhism, representing 'nothingness.' In 'Mukō,' it literally means the 'nothingness of effect.'

Guia de pronúncia

UK muːkəʊ

US muːkoʊ

The stress is even, but in Japanese pitch accent, it is usually 'Heiban' (flat) style: mu-ko-o.

Rima com

fukō (unhappiness) kikō (climate) ryokō (travel) shikō (thought) yūkō (validity) zukō (arts and crafts) eikō (glory) seikō (success)

Erros comuns

Pronouncing it like 'muko' (son-in-law) with a short 'o'.
Confusing it with 'mukō' (over there) which has a different pitch.
Over-emphasizing the 'u' sound.
Using English 'v' sounds for 'b' sounds in related words.
Misplacing the stress on the first syllable.

Nível de dificuldade

Leitura 3/5

The kanji are common but require knowledge of the 'effect' radical.

Escrita 4/5

Writing '効' can be tricky for beginners due to the number of strokes.

Expressão oral 2/5

Pronunciation is easy, but pitch accent matters.

Audição 2/5

Easy to recognize in context, but watch out for homophones.

O que aprender depois

Pré-requisitos

有効 (yūkō) 無し (nashi) 効果 (kōka) 切れる (kireru) 使う (tsukau)

Aprenda a seguir

失効 (shikkō) 解除 (kaijo) 法律 (hōritsu) 契約 (keiyaku) 手続き (tetsuzuki)

Avançado

瑕疵 (kashi) 公序良俗 (kōjo-ryōzoku) 遡及 (sokyū) 善意 (zenni) 悪意 (akui)

Gramática essencial

Ni naru / Ni suru with nouns

無効になる / 無効にする

Na-adjective noun modification

無効なデータ

Relative clauses

無効になったチケット

Passive voice with suru-verbs

無効化される

Formal 'to naru' transition

無効となります

Cadastre-se grátis para ler a explicação completa

Exemplos por nível

このチケットは無効です。

This ticket is invalid.

Noun + desu (Simple state).

カードが無効になりました。

The card became invalid.

Ni naru (Change of state).

それは無効だよ。

That's invalid (casual).

Casual sentence ending.

無効なパスワードです。

It is an invalid password.

Na-adjective modifying a noun.

このボタンは無効です。

This button is disabled.

Simple identification.

無効なコード。

Invalid code.

Noun phrase.

期限切れで無効です。

Expired and invalid.

Reason + de + result.

無効にしてください。

Please make it invalid (disable it).

Ni shite kudasai (Request action).

古い住所の書類は無効になります。

Documents with the old address will become invalid.

Future/Habitual change.

設定を無効にしましたか？

Did you disable the settings?

Past tense question.

名前がないチケットは無効です。

Tickets without a name are invalid.

Relative clause (nai) + noun.

このクーポンはもう無効だよ。

This coupon is already invalid.

Adverb 'mō' (already).

無効なメールアドレスです。

It is an invalid email address.

Standard error message format.

ルールを守らないと無効になるよ。

If you don't follow the rules, it will become invalid.

Condition 'to' (if/when).

そのパスは明日から無効です。

That pass is invalid from tomorrow.

Time + kara (from).

通知を無効に設定しました。

I set notifications to disabled.

Ni settei suru (to set to).

契約書にサインがない場合、契約は無効となります。

If there is no signature on the contract, the contract will be void.

To naru (Formal version of ni naru).

不正なアクセスを検知したため、キーを無効化しました。

Because unauthorized access was detected, the key was invalidated.

Mukōka (Deactivation/Invalidation).

間違えて無効なリンクをクリックしてしまった。

I accidentally clicked an invalid link.

Te shimau (Accidental action).

この法律は、新しい条例によって無効にされた。

This law was rendered invalid by a new ordinance.

Passive voice (sareta).

無効票が多いと、選挙の結果に影響します。

If there are many invalid votes, it affects the election results.

Conditional 'to' + influence.

セキュリティのために、古いセッションを無効にする必要があります。

For security reasons, it is necessary to invalidate old sessions.

Hitsuyō ga aru (Necessary to).

その主張は証拠がないため無効だと言わざるを得ない。

I have to say that claim is invalid because there is no evidence.

Iwazaru o enai (Cannot help but say).

無効な手続きを繰り返しても意味がありません。

There is no point in repeating invalid procedures.

Te mo imi ga nai (No point in doing).

手続き上の不備により、その決議は無効と見なされた。

Due to procedural flaws, that resolution was regarded as invalid.

To minasareru (To be regarded as).

一度無効になった権利を回復するのは難しい。

It is difficult to recover a right that has once become invalid.

Relative clause modifying 'kenri'.

この特許は新規性がないとして無効審判が請求された。

An invalidation trial was requested for this patent on the grounds of lack of novelty.

Mukō-shinpan (Invalidation trial).

ログイン試行が上限に達したため、アカウントを一時的に無効にします。

Because login attempts reached the limit, the account will be temporarily disabled.

Jōgen ni tassuru (Reach the limit).

契約の無効を主張するためには、強力な証拠が必要です。

In order to claim the invalidity of a contract, strong evidence is required.

Tame ni wa (In order to).

無効なデータを入力すると、システムがクラッシュする恐れがあります。

If you input invalid data, there is a risk the system might crash.

Osore ga aru (There is a risk/fear).

裁判所はその行政処分を無効と判示した。

The court ruled the administrative action as void.

To hanshita (Ruled/Judged that).

無効化された機能を再度有効にするには、再起動が必要です。

To re-enable a deactivated function, a restart is required.

Saido (Again/Once more).

公序良俗に反する契約は、当然に無効とされる。

Contracts that violate public order and morals are naturally rendered void.

Tōzen ni (Naturally/As a matter of course).

当該条項が無効であるとの司法判断が下された。

A judicial decision was handed down stating that the clause in question is invalid.

Tōgai (The said/In question).

意思能力を欠く状態で行われた法律行為は無効である。

Legal acts performed in a state lacking mental capacity are void.

Ishi-nōryoku (Mental capacity).

無効な婚姻の取り消しを求める訴えが提起された。

A lawsuit was filed seeking the annulment of an invalid marriage.

Teiki sareru (To be filed/brought).

憲法に違反する法律は、その効力を有せず、無効となる。

Laws that violate the Constitution do not have effect and become void.

Kōryoku o yusezu (Not possessing effect).

認証トークンが無効化されたため、APIへのアクセスが拒否された。

Because the authentication token was invalidated, access to the API was denied.

Kyohi sareru (To be denied).

錯誤に基づく意思表示の無効を主張する。

I claim the invalidity of the declaration of intent based on a mistake.

Sakugo (Mistake/Error in law).

無効な遺言書は、相続において法的拘束力を持たない。

An invalid will has no legal binding force in inheritance.

Hōteki-kōsokuryoku (Legal binding force).

法の支配において、適法性を欠く行政行為は無効の瑕疵を孕む。

Under the rule of law, administrative acts lacking legality contain the flaw of nullity.

Kashi o haramu (To contain/bear a flaw).

絶対的無効と相対的無効の差異は、第三者保護の観点から重要である。

The difference between absolute and relative nullity is important from the perspective of third-party protection.

Kanten (Perspective/Point of view).

その契約は通謀虚偽表示により、当事者間では無効となる。

The contract is void between the parties due to a conspiracy of false representation.

Tsūbō-kyogi-hyōji (Conspiracy of false representation).

無効な規定を分離し、残りの契約を有効に保つ「分離条項」が検討された。

A 'severability clause' was considered to separate invalid provisions and keep the rest of the contract valid.

Bunri-jōkō (Severability clause).

信義則に反する権利の行使は、実質的に無効と等しい。

The exercise of rights contrary to the principle of good faith is substantially equivalent to being invalid.

Shingisoku (Principle of good faith).

遡及的に無効となることで、既履行の給付には不当利得返還義務が生じる。

By becoming void retroactively, an obligation to return unjust enrichment arises for performances already rendered.

Sokyū-teki (Retroactive).

法的な無効性は、社会秩序の維持という要請から導き出される。

Legal invalidity is derived from the requirement of maintaining social order.

Yōsei (Requirement/Demand).

無効確認の訴えは、即時確定の利益がある場合に限り認められる。

An action for confirmation of invalidity is recognized only when there is an interest in immediate determination.

Kagiri mitomerareru (Recognized only when).

Colocações comuns

無効になる

無効にする

無効を宣言する

無効票

契約無効

無効化する

無効な形式

無効判決

無効試合

無効期間

Frases Comuns

無効を申し立てる

— To officially file a claim that something is invalid.

弁護士は契約の無効を申し立てた。

無効とされる

— To be rendered or regarded as invalid by an authority.

その行為は無効とされる。

一時的に無効

— Temporarily disabled or invalid.

アカウントは一時的に無効です。

全面的に無効

— Completely invalid.

その法案は全面的に無効だ。

遡及的に無効

— Invalid retroactively (from the start).

契約は遡及的に無効となった。

当然無効

— Naturally/Automatically invalid.

その規則は当然無効です。

無効な操作

— An invalid operation (often in computing).

無効な操作が行われました。

無効な署名

— An invalid signature.

無効な署名では受理できません。

無効を確認する

— To confirm the invalidity of something.

ステータスが無効であることを確認した。

無効を免れる

— To avoid being invalidated.

修正によって無効を免れた。

Frequentemente confundido com

無効 vs 向こう (mukō)

Means 'over there.' Sounds similar but has different kanji and meaning.

無効 vs 無駄 (muda)

Means 'waste.' Use for useless effort, not for rule-based invalidity.

無効 vs 無理 (muri)

Means 'impossible.' Use for things you can't do, not for validity.

Expressões idiomáticas

"無効に帰する"

— To come to nothing; to be rendered void or ineffective.

長年の努力が無効に帰した。

Formal/Literary

"白紙無効"

— Completely void, as if the paper were blank.

その合意は白紙無効だ。

Business/Legal

"無効の長物"

— A play on 'chōbutsu' (useless thing), referring to something large and invalid.

この古い法律は無効の長物だ。

Literary

"効力を持たない"

— To hold no power/effect (synonym for mukō).

そのルールはここでは効力を持たない。

Neutral

"形骸化する"

— To become a mere shell (lose real effect/become invalid in practice).

校則が形骸化している。

Academic

"実効性を失う"

— To lose practical effectiveness.

対策が実効性を失った。

Business

"有名無実"

— Existing in name only; having no substance/invalid in practice.

その役職は有名無実だ。

Common

"反故にする"

— To scrap; to treat as waste paper (to invalidate a promise/contract).

約束を反故にする。

Idiomatic

"取り付く島もない"

— Helpless/Invalid (in the sense of having no way to start).

交渉は無効で取り付く島もない。

Idiomatic

"無に帰す"

— To return to nothing (similar to mukō ni kisuru).

全てが無に帰した。

Literary

Fácil de confundir

無効 vs 失効 (shikkō)

Both deal with losing validity.

Shikkō is the act of expiring; Mukō is the state of being invalid.

パスポートが失効(shikkō)したので、今は無効(mukō)です。

無効 vs 取消 (torikeshi)

Both stop something from being valid.

Torikeshi is an active cancellation; Mukō often implies it was never valid or expired naturally.

予約を取り消す(torikeshi)と、その権利は無効(mukō)になる。

無効 vs 無用 (muyō)

Both start with 'Mu'.

Muyō means 'unnecessary' or 'forbidden'; Mukō means 'invalid'.

心配無用(muyō)だが、この券は無効(mukō)だ。

無効 vs 無力 (muryoku)

Both mean a lack of something.

Muryoku is for people (powerless); Mukō is for rules/things (invalid).

私は無力(muryoku)だが、彼の契約は無効(mukō)だ。

無効 vs 解除 (kaijo)

Both end a state.

Kaijo is specifically for terminating contracts or releasing locks.

契約を解除(kaijo)して無効(mukō)にする。

Padrões de frases

[Noun] は無効です。

この券は無効です。

[Noun] を無効にします。

通知を無効にします。

[Reason] ので、[Noun] は無効になりました。

期限が切れたので、チケットは無効になりました。

[Authority] によって [Noun] は無効と見なされる。

裁判所によって契約は無効と見なされる。

[Condition] に基づき、[Noun] の無効を主張する。

錯誤に基づき、契約の無効を主張する。

[Action] は [Concept] に反し、当然に無効である。

その行為は信義則に反し、当然に無効である。

無効な [Noun] を [Verb]。

無効なリンクをクリックした。

[Noun] が無効化されたため、[Result]。

アカウントが無効化されたため、ログインできない。

Família de palavras

Substantivos

無効化 (mukōka) - invalidation

無効性 (mukōsei) - invalidity

無効票 (mukōhyō) - invalid vote

Verbos

無効にする (mukō ni suru) - to invalidate

無効になる (mukō ni naru) - to become invalid

Adjetivos

無効な (mukō na) - invalid

Relacionado

有効 (yūkō) - valid

失効 (shikkō) - expiration

効力 (kōryoku) - effect

効果 (kōka) - effect/result

効率 (kōritsu) - efficiency

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Como usar

frequency

Very common in daily life, tech, and law.

Erros comuns

Using 'mukō' for 'impossible'. → 無理 (muri)
Mukō is about validity, Muri is about possibility.
Using 'mukō' for 'useless effort'. → 無駄 (muda)
Mukō is for rules/status, Muda is for wasted resources/time.
Writing '向こう' for 'invalid'. → 無効
向こう means 'over there'.
Saying 'mukō no hito' for a powerless person. → 無力な人 (muryoku na hito)
Mukō is not for people's abilities.
Confusing 'mukō' with 'shikkō'. → Depends on context.
Shikkō is the expiration process, Mukō is the resulting state.

Dicas

Using 'Ni Naru'

Always use 'ni naru' when you want to say something *became* invalid because of a deadline.

Kanji Precision

Ensure the 'Mu' kanji has the correct number of horizontal strokes (four in the middle).

Settings Menu

Look for 無効 (mukō) if you need to turn off or disable a feature in a Japanese app.

Polite Rejection

If someone gives you something invalid, say 'mōshiwake arimasen ga, kore wa mukō desu' to be polite.

Pairing Antonyms

Learn 'Yūkō' and 'Mukō' together as a set; they are high-frequency opposites.

Office Talk

Use 'mukōka' when discussing deactivating user accounts in a meeting.

JLPT Tip

This word often appears in reading sections about rules or announcements.

Pitch Accent

Try to keep your pitch flat for 'invalid' and rising for 'over there'.

Visual Aid

Visualize a 'Void' stamp hitting a paper; that stamp is the word 'Mukō'.

Avoid Muda

Don't say 'my study was mukō'; say 'my study was muda' if it didn't help.

Memorize

Mnemônico

Think of a 'Moo' (無) cow that has no 'Go' (効). It just sits there. It's invalid! No effect!

Associação visual

Imagine a big red 'X' over a contract or a ticket. The 'X' is the shape of the 'power' radical in the second kanji 効.

Word Web

Invalid Void Null Disabled Expired Useless No effect Rule-breaking

Desafio

Try to find 3 things in your house that are 'mukō' (expired coupons, old IDs, broken links) and say 'Kore wa mukō desu' for each.

Origem da palavra

Derived from Middle Chinese roots. 'Mu' (無) comes from the character for a dancer, later used for 'nothing.' 'Kō' (効) comes from 'to imitate' and 'power,' leading to the meaning of 'result' or 'effect.'

Significado original: To lack the power to produce a result.

Sino-Japanese (Kango).

Contexto cultural

Be careful not to use 'mukō' to describe a person's worth; use 'muryoku' (powerless) or other terms instead. 'Mukō' is for things and rules.

In English, we use 'invalid,' 'void,' or 'null.' In tech, we say 'disabled.' Japanese uses 'mukō' for all three.

Death Note (The rules of the notebook often use 'mukō' to describe invalid entries). Japanese Civil Code (Minpō) Article 90 (Public Order and Morals). Sumo wrestling (Referees calling a 'void' match).

Pratique na vida real

Contextos reais

Transport

無効なチケット
定期券が無効になる
改札口で無効と出る
期限切れで無効

Digital/Tech

設定を無効にする
無効なユーザー名
JavaScriptを無効化
リンクが無効

Legal/Business

契約の無効
無効を主張する
法的無効
署名が無効

Sports

無効試合
ゴールは無効
記録を無効にする
ファウルで無効

Elections

無効票の数
投票を無効にする
無効な名前
白紙は無効

Iniciadores de conversa

"このクーポン、まだ使えますか？それとも無効ですか？"

"間違えて設定を無効にしちゃったんだけど、どうすればいい？"

"選挙の無効票って、どうしてあんなに多いんだろうね？"

"契約書に不備があったら、全部無効になっちゃうのかな？"

"スポーツでせっかくのゴールが無効になった時、どう思う？"

Temas para diário

今日、無効（むこう）になったチケットやクーポンがありましたか？その時の気持ちを書いてください。

あなたが「これを無効にしたい！」と思うルールや法律はありますか？理由と一緒に書いてください。

デジタルの世界で「無効にする」機能はなぜ大切だと思いますか？

努力が無駄（むだ）になるのと、結果が無効（むこう）になるの、どちらが辛いですか？

日本の選挙での無効票について、あなたの意見を日本語でまとめてみましょう。

Perguntas frequentes

10 perguntas

No, it is used in sports (invalid goals), tech (disabled buttons), and daily life (expired coupons).

The opposite is 'yūkō' (有効), which means valid or effective.

Generally, no. For a person who is 'ineffective' or 'powerless,' use 'muryoku' (無力).

Yes, it can function as a na-adjective (mukō na) or a noun (mukō desu).

'Mukōka' (無効化) means the act of making something invalid, like deactivating a software feature.

You can say 'Kono rinku wa mukō desu' or 'Rinku ga kirete imasu'.

It is called 'mukō-hyō' (無効票).

Yes, it is a standard neutral word. Use 'desu' to make it polite.

It is better to say 'kōka ga nai' (no effect) for medicine, though 'mukō' is technically possible in a clinical sense.

That is 'mukō' (向こう), written with different kanji. They are homophones.

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