Translation guide
How to express that an action or outcome was not intended, covering accidents, unconscious actions, and lack of intent.
The speaker did something by mistake or without meaning to.
Attach to the te-form of a verb to express that an action happened unintentionally, often with a sense of regret. 〜ちゃう is the casual contraction.
I accidentally ate all the cake.
I dropped my wallet (by accident).
An adverb meaning 'carelessly' or 'inadvertently'. Often used with 〜てしまう to emphasize the accidental nature.
I carelessly forgot the appointment.
I accidentally missed my stop.
Adverb meaning 'without thinking' or 'in spite of oneself', used for actions done impulsively or against one's better judgment.
I ended up eating too much without meaning to.
I unintentionally blurted out the secret.
Adverb meaning 'involuntarily' or 'without thinking', used for spontaneous reactions.
I laughed unintentionally.
I screamed without meaning to.
The speaker did something without being aware of it, but not necessarily a mistake.
Adverb meaning 'unconsciously' or 'without realizing'. Used for actions done without conscious thought.
I was unconsciously touching my hair.
I was unintentionally humming the same song.
Adverb meaning 'without knowing' or 'unconsciously', often for gradual, unnoticed actions.
Adverb meaning 'casually' or 'without much thought', often for actions done unintentionally but without negative connotation.
Stating that something was not done on purpose, often in formal or explanatory contexts.
Formal phrase meaning 'not intentional'. Used in serious situations to deny intent.
That was unintentional.
Casual phrase meaning 'it wasn't on purpose'. Common in everyday speech.
It was unintentional! / I didn't do it on purpose!
Noun/adjective meaning 'unintentional' or 'against one's will', often used in formal writing.
〜てしまう is a grammatical pattern that adds the nuance of unintentional action to any verb. うっかり emphasizes carelessness, while つい implies acting against one's better judgment or impulse. They are often combined: うっかり〜てしまう, つい〜てしまう.
I carelessly told the secret.
I ended up telling the secret (even though I knew I shouldn't).
English 'unintentional' is often an adjective, but Japanese expresses this concept more naturally through adverbs and verb endings. Avoid literal translations like 意図的でない in casual speech; use the patterns above instead.
Unintentionally, I had picked up a bad habit.
A remark I made unintentionally hurt him.
不本意な結果に終わった。
It ended in an unintentional result.