Translation guide
Expressing that an action cannot be done, is not feasible, or is beyond one's ability. Japanese uses potential forms, set phrases, and contextual strategies rather than a single word.
Express that an action is impossible or cannot be performed due to lack of ability, circumstances, or rules.
The most direct way to say 'cannot do' is to use the negative potential form of the verb. For ru-verbs, replace 〜る with 〜られない; for u-verbs, change the final -u to -eない; for する, use できない; for 来る, use 来られない.
I can't read this kanji.
He can't swim.
I can't come tomorrow.
The negative potential of する, meaning 'cannot do'. Used for actions expressed with する verbs or when the verb is clear from context.
I can't do my homework.
Means 'it's impossible' or 'no way'. Stronger than できない, often implying the task is beyond one's power or unreasonable. Casual form; polite is 無理です.
It's impossible to carry it alone.
Formal/literary word for 'impossible'. Used in technical or serious contexts. Not common in everyday speech.
That plan is impossible.
Express that something is inherently impossible, not just that a specific person cannot do it.
To say something 'cannot be done' (impersonal), use the negative potential of the passive form, or simply the negative potential if the subject is inanimate. Often 〜ことができない or 〜られない.
Express that something is impossible because it is too hard or beyond one's skill.
Attach to verb stem to mean 'cannot finish/complete doing' or 'cannot fully do'. Implies the task is too much to handle.
I can't eat it all.
Express that an action is impossible because of the situation, not personal ability.
Means 'this is no time for doing' or 'far from being able to do'. Indicates the situation prevents the action.
English speakers often overuse 不可能 (fukanō). In daily conversation, use potential form negatives (できない, 〜られない) or 無理 (muri) instead. 不可能 sounds stiff and technical.
できない is neutral 'cannot do'. 無理 implies the task is unreasonable or beyond one's limits. Use 無理 for stronger emphasis or when refusing a request.
そんなこと、できないよ。
I can't do something like that.
This door cannot be opened.
That problem cannot be solved.
Used when something cannot be done due to social, moral, or practical constraints. 'It's not possible (because it would be wrong/irresponsible).'
I can't break a promise.
Literally 'there is no way to do'. Emphasizes the lack of method or means.
There's no way to contact (him/her).
数えきれない。
Too many to count.
Formal expression meaning 'cannot bring oneself to do' or 'find it difficult to do'. Often used in business.
I cannot agree to that proposal.
Now is not the time for traveling.
Cannot afford to do; cannot be doing something given the circumstances.
I can't be crying (at a time like this).