訳わけ知しり顔がお

noun

know-it-all airs; I-know-how-it-is look

Describes a facial expression or attitude of someone acting as if they understand everything, often with a hint of smugness.

• 彼かれはいつも訳わけ知しり顔がおで話はなす。

  He always talks with a know-it-all air.

• 新しん入にゅう社しゃ員いんのくせに、訳わけ知しり顔がおでアドバイスするな。

  Don't give advice with an I-know-how-it-is look when you're just a new employee.