눈치가 · 눈치를
tact, social awareness, sense for others' feelings; someone's mood or reaction
Example
그 친구는 눈치가 없어서 자주 실수해요.
That friend has no social awareness, so he often makes blunders.
Word parts
Probably built on 눈 'eye' — reading the room with your eyes.
Good to know
A key cultural idea: quietly sensing what others think or want without being told.