Translation guide
The English phrase "keep to oneself" has two main meanings: (1) to avoid socializing or prefer solitude, and (2) to keep information secret. Japanese expresses these ideas with different verbs, adjectives, and set phrases depending on the nuance.
He keeps to himself.
Describes someone who prefers solitude.
Keep it to yourself.
Casual way to say 'don't tell anyone'.
Describing a person who does not seek out company, stays alone, or is reserved.
He's quiet and keeps to himself. · She prefers to keep to herself at parties.
Literally 'to be alone'. A natural, neutral way to say someone keeps to themselves, without negative connotation.
He always keeps to himself during breaks.
Means 'doesn't interact much with people'. Useful for describing someone who avoids social contact.
She keeps to herself at work.
Idiom meaning 'to withdraw into one's shell'. Suggests a more deliberate or emotional retreat from others.
Since the breakup, he's been keeping to himself.
Adjectival noun meaning 'introverted'. Describes a personality trait, not just behavior.
He has an introverted personality and keeps to himself.
Literary word meaning 'aloof' or 'standing alone in noble isolation'. Implies a proud, solitary stance.
He is known as a writer who keeps to himself.
Telling someone not to share information, or describing that something is kept confidential.
Keep it to yourself! · I'll keep your secret to myself.
Common, casual phrase meaning 'to keep secret'. Often used among friends or family.
Keep this to yourself, okay?
Standard phrase for 'to keep a secret'. Slightly more formal than 内緒.
Formal expression meaning 'not to disclose'. Used in serious or official contexts.
Literary phrase meaning 'to keep in one's heart'. Implies deep, often emotional secrecy.
Means 'to stay silent'. Can imply keeping something to oneself by not speaking about it.
内緒 (naisho) is casual and often used for personal, everyday secrets. 秘密 (himitsu) is more formal and can be used for official or serious secrets. In friendly conversation, 内緒 is more natural.
This is just between us.
State secrets must be kept confidential.
Do not translate 'keep to oneself' literally as 自分に保つ or similar. It will not be understood. Use the phrases above depending on the intended meaning.
He kept the plan to himself.
Please keep this information to yourself.
He kept those feelings to himself.
He kept it to himself and said nothing.