은근해요 · 은근했어요 · 은근한 (+noun)
subtle, quiet, understated; warm in a low-key way
Example
그 사람은 말은 없지만 정이 은근해요.
He doesn't talk much, but he's quietly warm-hearted.
Word parts
From hanja meaning 'earnest, attentive'; now 'quiet and understated'.
Good to know
The adverb 은근히 is very common in speech: 은근히 기대돼요 'I'm secretly looking forward to it.'
Related words