Translation guide
The English word 'mouth' refers to the body part, but also extends to openings, expressions, and speech. This guide covers natural Japanese equivalents for each meaning.
The physical mouth (lips, oral cavity) of a person or animal.
The standard word for 'mouth'. Used for humans and animals.
口を大きく開けてください。
Please open your mouth wide.
猫が口をなめている。
The cat is licking its mouth.
The opening of a container, cave, river, etc.
Referring to speaking, verbal expression, or the source of words.
To butt in, to interfere verbally. Literally 'put out one's mouth'.
人の話に口を出さないで。
Don't butt into other people's conversations.
To be loose-lipped, to have a big mouth (revealing secrets).
To be tight-lipped, able to keep a secret.
彼女は口が堅いので信頼できる。
She is trustworthy because she is tight-lipped.
To mention, to say, to put into words. Also means to eat or drink.
Tone of voice, way of speaking.
Referring to one's palate or taste in food.
To suit one's taste, to be palatable.
この料理は私の口に合わない。
This dish doesn't suit my taste.
Referring to consumption or the number of people to feed.
To put into one's mouth, to eat or drink.
彼は何も口に入れなかった。
He didn't put anything in his mouth.
Reducing the number of mouths to feed (historical/sociological term).
口減らしのために奉公に出された。
They were sent to work to reduce the number of mouths to feed.
While 'mouth' is usually translated as 口 (くち), many English idioms using 'mouth' do not translate directly. For example, 'big mouth' (talkative person) is not 大きい口 but 口が軽い or おしゃべり. Always check the natural Japanese expression.
口 refers to the entire mouth (including inside), while 唇 specifically means 'lips'. Use 唇 when talking about lipstick, kissing, or chapped lips.
I fished at the mouth of the river.
Be careful because he has a big mouth.
I don't want to mention his name.
His tone of voice suddenly changed.