閉へい口こう頓とん首しゅ

noun, noun or participle which takes 'suru'

at a complete loss; at one's wit's end; at a loss for an answer

A yojijukugo describing a state of being utterly stumped, unable to think of what to do or say. Often used in formal or literary contexts.

• 彼かれの理り不ふ尽じんな要よう求きゅうには閉へい口こう頓とん首しゅした。

  I was at a complete loss in the face of his unreasonable demands.

• あまりの難なん問もんに、一いち同どう閉へい口こう頓とん首しゅの体ていだった。

  Faced with such a difficult problem, everyone was at their wit's end.