口(くち)が堅(かた)い

くちがかたい
expression
tight-lipped, discreet
businessexpression
1. tight-lipped, discreet, able to keep secrets
Describes someone who can be trusted with confidential information and won't reveal it to others.
彼女(かのじょ)は口(くち)が堅(かた)いから安心(あんしん)だ。
She can keep a secret, so I feel safe.
口(くち)の堅(かた)い人(ひと)にしか話(はな)せない。
I can only tell this to someone who can keep a secret.
秘書(ひしょ)は口(くち)が堅(かた)くなければならない。
A secretary must be tight-lipped.
口(くち)が堅(かた)いと分(わ)かると、みんなが相談(そうだん)に来(く)るようになった。
Once people realized I was discreet, everyone started coming to me for advice.
彼(かれ)は口(くち)が堅(かた)いので、会社(かいしゃ)の大事(だいじ)な情報(じょうほう)を任(まか)されている。
He's tight-lipped, so he's entrusted with important company information.

Structure: 口(くち) (mouth) + が + 堅(かた)い (hard/firm). Literally 'one's mouth is firm' - implying words don't escape easily.

Antonym: 口(くち)が軽(かる)い (loose-lipped, indiscreet)

Prenominal form: 口(くち)の堅(かた)い + noun (a discreet [person])

Related words

Cultural note: Being 口(くち)が堅(かた)い is considered a valuable trait in Japanese business and personal relationships.

Related Words

Antonym: 口(くち)が軽(かる)い (loose-lipped)
Compare: 秘密(ひみつ)主義(しゅぎ) (secretiveness)
Compare: 口(くち)が滑(すべ)る (to let something slip)

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Body-Part Idioms
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Added 2026.1.18 19:03 · Revised 2026.9.2 13:01
06500/06885_kuchigakatai