Expressions (phrases, clauses, etc.), Godan verb with 'su' ending
to expose one's faults; to have one's defects exposed; to show oneself up
あいつでかいことばかり言ってるけど、そのうちぼろを出すよ。He's always talking like a big shot, but it won't be long before all his faults are exposed.
Also written ぼろを出す【ぼろをだす】