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.
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.
彼は休み時間はいつも一人でいる。
He always keeps to himself during breaks.
Means 'doesn't interact much with people'. Useful for describing someone who avoids social contact.
彼女は職場であまり人と関わらない。
She keeps to herself at work.
Idiom meaning 'to withdraw into one's shell'. Suggests a more deliberate or emotional retreat from others.
失恋してから、彼は自分の殻に閉じこもっている。
Since the breakup, he's been keeping to himself.
Adjectival noun meaning 'introverted'. Describes a personality trait, not just behavior.
彼は内向的な性格で、人付き合いが苦手だ。
He has an introverted personality and keeps to himself.
Literary word meaning 'aloof' or 'standing alone in noble isolation'. Implies a proud, solitary stance.
彼は孤高の作家として知られている。
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.
このことは内緒にしておいてね。
Keep this to yourself, okay?
Standard phrase for 'to keep a secret'. Slightly more formal than 内緒.
彼はその計画を秘密にしていた。
He kept the plan to himself.
Formal expression meaning 'not to disclose'. Used in serious or official contexts.
この情報は口外しないでください。
Please keep this information to yourself.
Literary phrase meaning 'to keep in one's heart'. Implies deep, often emotional secrecy.
彼はその思いを胸に秘めていた。
He kept those feelings to himself.
Means 'to stay silent'. Can imply keeping something to oneself by not speaking about it.
彼は何も言わずに黙っていた。
He kept it to himself and said nothing.
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.
これは内緒だよ。
This is just between us.
国家機密は秘密にしなければならない。
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.