못을 박아요 · 못을 박았어요 · 못 박아 두다
to make something clear; to state firmly
Example
사장님은 이번에는 연장이 없다고 못을 박았어요.
The boss made it clear there would be no extension this time.
Word parts
Literally 'to hammer in a nail,' fixing a point so it won't move.
Good to know
가슴에 못을 박다 is different: to hurt someone deeply.