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.
That's a secret.
Please keep the secret.
A personal or informal secret, often between friends or family. Implies 'just between us'.
This is just between us.
I have a secret to tell you.
Classified or confidential information, often used in military, government, or corporate contexts.
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...'.
What's the secret to your success?
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.
She keeps her past a secret.
To keep something a secret (informal). Often used when asking someone not to tell others.
Keep this a secret, okay?
To keep something secret (neutral/formal).
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.
a secret room
a secret passage
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.
Can you keep a secret?
Polite form. Casually: 内緒にできる？ (naisho ni dekiru?)
It's no secret that he's rich.
公然の秘密 (kōzen no himitsu) means 'open secret'.
彼の成功の秘密は努力だ。
The secret to his success is hard work.
その流派の奥義は門外不出だ。
The secret techniques of that school are not revealed to outsiders.
隠し扉
a secret door
a secret ingredient (in cooking)
a secret recipe (handed down)