expression, noun-modifying (irregular)
Prenominal phrase describing a person or action as foolish, slow-witted, or lacking common sense. Often used in a mildly insulting or exasperated tone.
間の抜けた質問をするな。
Don't ask such a stupid question.
彼は間の抜けた顔で立っていた。
He stood there with a vacant look on his face.