박장대소가 · 박장대소를 (often 박장대소하다)
roaring with laughter (while clapping one's hands)
Example
친구의 농담에 모두 박장대소했어요.
Everyone roared with laughter at my friend's joke.
Word parts
박 clap+장 palm+대 big+소 laugh
Literally 'clap the palms and laugh loudly'.
Good to know
Pronounced [박짱대소]. A bit literary; in casual speech people say 빵 터지다 or 배꼽을 잡다.