안녕히 가세요
annyeonghi gaseyo · TOPIK 1
goodbye (to someone leaving)
👋 안녕히 (in peace) + 가세요 (please go) = go in peace
안녕 is the same peace/well-being as in 안녕하세요 (hello). 가 comes from 가다, to go, with the polite ending -세요. You say it to the person who is leaving; if you are the one leaving, 가세요 swaps for 계세요 (please stay).