大だいチョンボ

noun, noun or participle which takes 'suru'

big goof; serious mistake

Colloquial term for a major blunder or careless error, often used in casual or self-deprecating contexts. Derived from ちょんぼ (small mistake) with 大 (big) added for emphasis.

See also: ちょんぼ

• 会かい議ぎで大だいチョンボをやらかしてしまった。

  I made a huge blunder at the meeting.

• あんな大だいチョンボをしたら