殺す

The Japanese verb 殺す (korosu) is a primary transitive verb that translates most directly to 'to kill' or 'to cause the death of' in English. While the core meaning is straightforwardly biological—ending the life of a living organism—its application in Japanese spans a wide spectrum from literal violence to highly nuanced metaphorical expressions. In its most basic form, it is used for insects, animals, and humans. However, unlike some languages where 'kill' might feel overly harsh for small things, korosu is the standard term for swatting a mosquito (蚊を殺す) as well as the heavy term used in criminal law. Understanding korosu requires a grasp of its transitive nature; it always implies an agent (a killer) performing an action upon a target (the victim).

Biological Termination

This is the literal act of ending a life. It is used in news reports, history books, and daily life when dealing with pests. For example, 害虫を殺す (killing harmful insects).

Metaphorical Suppression

In a more abstract sense, korosu refers to the suppression or 'killing' of non-living things like sounds, emotions, or light. 息を殺す (iki o korosu) means to 'kill one's breath' or hold it silently to avoid detection, a common phrase in suspenseful literature.

Beyond the physical and emotional, korosu is used in technical and artistic contexts. For instance, in design or fashion, one might speak of 'killing' a color's vibrancy (色を殺す) to make another element stand out. This usage aligns with the idea of neutralizing or negating the effectiveness of something. In sports, 'killing' the ball or the opponent's momentum uses this same verb. The cultural weight of the word is significant; Japan has strict social taboos regarding death, yet the word is ubiquitous in pop culture. This duality means a learner must be careful: understand it well for comprehension, but use it sparingly in speech.

Idiomatic Use: Time

Much like English, Japanese uses 'killing time' (時間を潰す - jikan o tsubusu), but korosu is rarely used for time. Instead, tsubusu (to crush) is the standard. Using korosu for time would sound like you are literally murdering the concept of time itself, which is a common mistake for English speakers.

Finally, the word appears in several set phrases related to 'suppressing' one's self. 自分を殺す (jibun o korosu) means to suppress one's own desires or personality for the sake of harmony or a greater goal. This reflects the collectivist nature of Japanese society where individual 'killing' of the ego is sometimes viewed as a virtue in professional or familial contexts. Thus, korosu is not just about the end of life, but the strategic negation of presence, sound, and self-will.

殺す (korosu) is a Group 1 (u-verb or Godan verb). Its conjugation follows the standard pattern for verbs ending in -su. Because it is a transitive verb, it almost always takes the direct object marker を (o). The basic structure is: [Subject] が [Object] を 殺す. For example, 'The cat killed the mouse' would be 猫がネズミを殺した (Neko ga nezumi o koroshita).

The Passive Form: 殺される

In news reporting, the passive form 殺される (korosareru) is extremely common. It shifts the focus to the victim. 彼は強盗に殺された (He was killed by a robber). Note that the agent of the action (the killer) is marked with に (ni).

The Causative Form: 殺させる

The causative form 殺させる (korosaseru) means 'to make/let someone kill.' This is often used in historical dramas (Jidaigeki) where a lord might order a subordinate to kill someone. 部下に敵を殺させた (He made his subordinate kill the enemy).

One of the most important grammatical nuances involves the 'te-form' plus auxiliary verbs. 殺してしまう (koroshite shimau) implies that the killing happened accidentally or with a sense of regret. For example, if you accidentally stepped on a beetle, you would say 虫を殺してしまった. Conversely, 殺してやる (koroshite yaru) is a highly aggressive, threatening form often used by villains in stories, implying a 'favor' of killing the opponent.

In metaphorical usage, the grammar remains the same. When killing a sound or a presence, you still use the を particle. 物音を殺す (monooto o korosu) means to stifle a sound. In these cases, the verb functions as a way to describe extreme control over one's environment or self. Interestingly, korosu can also be used in the imperative form 殺せ! (Korose!), which is a harsh command to kill. This is strictly limited to military or fictional contexts. In polite society, if one must discuss the act of killing (such as in a legal or medical context), more formal verbs like 殺害する (satsugai suru) are preferred over the raw, native korosu.

Compound Verbs

Korosu often appears as the second element in compound verbs like ぶち殺す (buchikorosu - to beat to death) or 刺し殺す (sashikorosu - to stab to death). These compounds specify the method of killing and are very common in descriptive writing.

The word 殺す (korosu) is ubiquitous in Japanese media, yet relatively rare in polite, everyday conversation. If you are watching a detective drama like Detective Conan (Meitantei Konan), you will hear it in every episode. The phrase 犯人はどうやって彼を殺したのか？ (How did the culprit kill him?) is a staple of the genre. Similarly, in shonen manga like Dragon Ball or Demon Slayer, the word is used constantly during battles. It serves to raise the stakes of the conflict, making it a matter of life and death.

News and Journalism

When a murder occurs, news anchors use the term 殺人事件 (satsujin jiken - murder case). While the noun form is used for the event, the verb korosu is used in interviews with witnesses or when describing the suspect's actions: 「殺すつもりはなかった」と容疑者は供述しています ('I didn't intend to kill him,' the suspect is stating).

In everyday life, you might hear korosu in the context of pest control. A parent might tell a child, 蚊を殺しなさい (Kill the mosquito). However, many Japanese people, especially those who follow Buddhist-influenced values of compassion toward all living things, might prefer the word 退治する (taiji suru - to exterminate/get rid of) or even 逃がす (nigasu - to let go) for insects. The choice of korosu vs. taiji suru can reflect the speaker's personality or the level of annoyance caused by the pest.

Another common place to hear korosu is in historical settings, such as Samurai films or novels. Here, the word is used with a sense of gravity and ritual. The act of 介錯 (kaishaku), the beheading of someone performing seppuku, is a specific form of 'killing' that is discussed with high formality. In these contexts, korosu is often replaced with more specific verbs like 斬る (kiru - to cut/slay with a sword). Understanding when korosu is used instead of a specific method-verb tells you about the speaker's intent—korosu focuses purely on the result: the death.

Idiomatic Silence

In suspenseful movies, characters often whisper 息を殺せ (iki o korose - hold your breath). This is a very common phrase that learners will encounter in any thriller or horror context. It emphasizes the tension of the scene by suggesting that even the sound of breathing could be fatal.

One of the most frequent errors for English speakers is confusing 殺す (korosu) with 死ぬ (shinu). In English, 'to kill' (transitive) and 'to die' (intransitive) are distinct, and the same is true in Japanese. However, learners often mix up the subjects. Remember: [A] が [B] を 殺す (A kills B) vs. [B] が 死ぬ (B dies). You cannot say *彼が殺した to mean 'He died.' That would mean 'He killed (someone).'

Mistake: Killing Time

As mentioned previously, do not use korosu for time. In English, 'killing time' is a lighthearted way to say you are waiting. In Japanese, 時間を殺す sounds like a sci-fi concept or a poetic, dark expression. Use 時間を潰す (jikan o tsubusu) instead.

Over-Aggression in Speech

Anime fans often pick up the word korosu and use it jokingly with friends. In Japanese culture, this is much riskier than in English. Threatening language, even in jest, is taken very seriously. Using 殺すぞ！ (I'll kill you!) can result in being banned from establishments or even police intervention. It is best to avoid using this word toward people entirely.

Another mistake is the misuse of the causative form. Some learners use 殺させる when they mean they 'had someone killed' (ordered a hit), which is correct, but they might also use it when they mean 'forced someone to die.' For the latter, 死なせる (shinaseru - to let/make die) is more appropriate if the person didn't die by an act of killing but by negligence or circumstances. For example, 'The doctor let the patient die' would use 死なせた, not 殺させた.

Finally, beware of the kanji. While korosu is usually written as 殺す, in very rare, highly specific historical or legal contexts, you might see other characters, but for 99% of learners, 殺 is the only one you need. Also, ensure you don't confuse the radical of 殺 (which includes the 'weapon' radical 殳) with similar-looking characters like 役 (duty) or 設 (establish).

While 殺す (korosu) is the most general term, Japanese has many synonyms that are used depending on the method, the target, and the level of formality. Choosing the right one is key to sounding natural and respectful (where applicable).

殺害する (Satsugai suru)

This is the formal, 'Sino-Japanese' (kango) version of korosu. It is used in news reports, legal documents, and formal writing. It specifically refers to the murder of a human being. You would never use satsugai suru for a mosquito.

倒す (Taosu)

Literally 'to knock down' or 'to defeat.' This is the standard term in video games and sports. It is much softer than korosu. If you 'defeat' a boss in a game, you 倒す him. It implies victory without necessarily focusing on the gore of death.

退治する (Taiji suru)

Used for exterminating pests, demons (oni), or villains. It has a nuance of 'ridding the world of an evil/nuisance.' It is more socially acceptable when talking about bugs than korosu.

葬る (Hofuru)

A more literary or dramatic term meaning 'to slaughter' or 'to bury.' It is often used figuratively, like 闇に葬る (yami ni hofuru - to bury in the darkness/cover up a secret).

For metaphorical 'killing' of emotions or sounds, 抑える (osaeru) or 隠す (kakusu) are common alternatives. While 感情を殺す (suppress emotions) implies a total, cold eradication of feeling, 感情を抑える (hold back emotions) sounds more like a temporary struggle for control. Similarly, 声を殺す (stifle a voice) is more intense than 声を小さくする (lower one's voice), suggesting a desperate need for absolute silence.

In historical or martial contexts, specific verbs like 刺す (sasu - stab), 射る (iru - shoot an arrow), or 絞める (shimeru - strangle) are used to be more descriptive. Korosu remains the umbrella term for the outcome of all these actions.