정당해요 · 정당했어요 · 정당한 (+noun)
just, fair, legitimate
Example
일한 만큼 정당한 대가를 받아야 해요.
You should get fair pay for the work you do.
Word parts
정 right+당 proper
Literally 'right and proper'.
Good to know
Don't confuse with 정당 'political party' (政黨), a different word with the same sound.
Related words