知しったかぶり

noun, noun or participle which takes 'suru'

pretending to know; acting like one knows

Often used for someone who feigns knowledge or expertise, especially in casual conversation. Can be used as a noun or with する to describe the act.

• 彼かれはいつも知しったかぶりをして、話はなしに入はいってくる。

  He always pretends to know and joins the conversation.

• 知しったかぶりはやめたほうがいいよ。

  You'd better stop pretending to know.