thick as champ

Adjective

Hiberno-English informal not-comparable

(informal, Hiberno-English) Very ignorant or foolish, sullen or in a bad temper.

Japanese Meaning

（口語、ヒバニョン）非常に無知で愚か、あるいは不機嫌で怒りっぽい状態を指す

Don't be thick as champ about it; just tell me what happened.

そんなに無知で不機嫌にならないで、ただ何があったか話してよ。

Sense（1）

(informal, Hiberno-English) Very ignorant or foolish, sullen or in a bad temper.