also: くそどきょう
noun
foolhardy courage; reckless bravery
Describes a boldness that borders on stupidity; often used in a negative or mocking tone. The prefix クソ adds emphasis, similar to 'damn' or 'stupid' in English.
あいつはクソ度胸だけで勝負に挑んだ。
He took on the challenge with nothing but reckless courage.
クソ度胸があるから、あんな危ないことも平気でやるんだ。
Because he has foolhardy courage, he does dangerous things without a second thought.
度胸 means 'courage' or 'nerve' in a neutral or positive sense, while クソ度胸 adds a derogatory or mocking nuance, implying the courage is reckless or foolish.
Compound of the vulgar intensifier クソ (kuso, 'damn') and 度胸 (dokyō, 'courage'). The exact origin is uncertain, but it likely arose as a colloquial, emphatic expression.