수고하세요 · 수고하셨습니다 (after work is done)
keep up the good work; take care (said when leaving)
Example
오늘 커피 정말 맛있게 잘 마셨어요. 수고하세요!
The coffee was really good today. Have a good one!
Word parts
수 receive+고 hardship
Literally 'endure hardship' — acknowledging someone's effort.
Good to know
Said to clerks or coworkers when leaving; avoid it with your boss or elders — use 수고하셨습니다 or 먼저 가 보겠습니다.