Translation guide
The English word 'secret' can refer to confidential information, a hidden method, or something kept private. In Japanese, the most common equivalent is 秘密 (himitsu), but depending on context, other words like 内緒 (naisho) for personal secrets or 機密 (kimitsu) for classified information are used. This guide covers how to express these nuances naturally.
Something known only to a few people and not to be revealed.
The most general and common word for 'secret'. Used for personal, professional, or official secrets.
それは秘密です。
That's a secret.
秘密を守ってください。
Please keep the secret.
A personal or informal secret, often between friends or family. Implies 'just between us'.
Classified or confidential information, often used in military, government, or corporate contexts.
機密文書が漏洩した。
Classified documents were leaked.
A secret way of doing something, a trick, or a hidden technique.
The secret to success or a special technique. Often used in phrases like 'the secret to...'.
成功の秘訣は何ですか？
What's the secret to your success?
長生きの秘訣を教えてください。
Please tell me the secret to a long life.
Can also be used for a hidden method, but 秘訣 is more specific for techniques.
Esoteric or secret principles, often in martial arts or traditional arts. Very niche.
Not openly known or revealed; personal privacy.
General term for something kept private.
彼女は自分の過去を秘密にしている。
She keeps her past a secret.
To keep something a secret (informal). Often used when asking someone not to tell others.
このことは内緒にしておいて。
Keep this a secret, okay?
To keep something secret (neutral/formal).
その計画は秘密にされた。
The plan was kept secret.
Describing something that is secret or hidden.
The most common way to say 'secret [something]'. 秘密の is the adjectival form.
Prefix meaning 'hidden' or 'secret', used in compounds like 隠し扉 (hidden door).
Prefix used in formal compounds like 秘書 (private secretary) or 秘伝 (secret tradition). Not used alone.
秘伝のレシピ
a secret recipe (handed down)
秘密 (himitsu) is the standard, neutral word for 'secret' and can be used in any context. 内緒 (naisho) is more casual and implies a personal, often trivial secret shared between close individuals. Use 内緒 with friends or family; use 秘密 in formal or serious situations.
English often uses 'secret' as an adjective directly (e.g., 'secret agent'). In Japanese, you usually need の (no) to connect 秘密 to a noun: 秘密のエージェント. Avoid using 秘密 alone as a prefix.
The secret to his success is hard work.
The secret techniques of that school are not revealed to outsiders.