독불장군이 · 독불장군을
lone wolf, someone who insists on doing everything their own way
Example
그는 독불장군처럼 혼자서 모든 결정을 내려요.
Like a lone wolf, he makes every decision by himself.
Word parts
독 alone+불 not+장 general+군 army
Literally 'alone, one cannot be a general' — now used for someone who ignores everyone else.
Good to know
Pronounced [독뿔장군]; it's a criticism, so avoid using it about someone to their face.