口くち軽がる

na-adjective, noun

loose-lipped; talkative

Describes a person who cannot keep secrets or who talks too freely. Often used in a negative sense.

• 彼かれは口くち軽がるだから、秘ひ密みつを話はなさないほうがいい。

  He's loose-lipped, so you'd better not tell him secrets.

• 口くち軽がるな人ひとに大だい事じな話はなしは任まかせられない。

  You can't entrust important matters to a talkative person.