big frog in a small pond
自誇自大，過於自信，但實際上只在小圈子中有影響力或表現出色
口语·讽刺在小圈子中自以为是的人
英文释义
To be a prominent or important person in a small or limited setting or group, but potentially insignificant or unimportant in a larger or more competitive context
例句
He thinks he's a big frog in a small pond, but in the city he's just average.
典故来源
与'big fish in a small pond'同源，强调自大和局限性，'frog'更带贬义。