Translation guide
Expresses that one has no choice but to do something, or that a certain action or feeling is inevitable. In Japanese, this is conveyed through set grammatical patterns rather than a single word.
The speaker feels compelled to take an action, often reluctantly, because there is no other option.
I cannot but oppose his opinion.
Due to bad weather, we had no choice but to cancel the game.
Means 'cannot not do' or 'must do' due to social obligation, duty, or common sense. Stronger sense of obligation than ～ざるを得ない.
Since my boss asked me, I cannot but do it.
It's my friend's wedding, so I cannot but go.
A casual pattern meaning 'there is nothing but to do' or 'have no choice but to do'. Used with the dictionary form of the verb. Emphasizes the lack of alternatives.
There's no bus, so I cannot but walk.
No one will help, so I have no choice but to do it myself.
A slightly more formal or literary version of ～しかない, meaning 'there is no other way but to do'. Often used in writing.
Now that it's come to this, we cannot but fight to the end.
The speaker experiences an involuntary emotional or physical reaction, or does something without intending to.
Means 'cannot help doing' or 'cannot resist doing'. Expresses an uncontrollable urge or feeling. Used with the negative stem (ない-stem) of the verb.
Hearing that story, I couldn't but laugh.
When I hear her sing, I cannot but be moved.
Similar to ～ずにはいられない, but slightly more colloquial. Also means 'cannot help doing'.
While primarily meaning 'to do completely' or 'to end up doing', it often implies an unintended or regrettable action, similar to 'cannot but do' in certain contexts. Often used with つい.
I couldn't but overeat (I ended up overeating without meaning to).
Expresses that a situation is unavoidable or a natural consequence.
Means 'it's no wonder that' or 'it's only natural that'. Used to say that a reaction or outcome is inevitable given the circumstances.
It cannot be helped that he gets angry (He cannot but get angry).
Means 'it is natural that' or 'it is to be expected that'. Similar to ～のも無理はない but more direct.
～ざるを得ない emphasizes that the action is unavoidable due to external circumstances, often reluctantly. ～ないわけにはいかない emphasizes a social or moral obligation that makes not doing the action impossible.
If the game is canceled due to rain, we have no choice but to go home. (external factor)
If a friend is in trouble, I cannot but help. (moral obligation)
There is no single Japanese word for 'cannot but do'. Using a direct translation like できないがする is incorrect. Always use the appropriate grammatical pattern based on the nuance you want to convey.
When I watch a scary movie, I cannot but scream.
Since they practiced that much, they cannot but win (it's only natural they win).