청산유수가 · 청산유수를
speaking fluently and eloquently, a smooth talker
Example
그는 처음 보는 사람 앞에서도 말을 청산유수처럼 잘해요.
Even in front of strangers, he talks as smoothly as a flowing stream.
Word parts
청 blue+산 mountain+유 flow+수 water
Literally 'water flowing past green mountains' — speech that never snags.
Good to know
Usually 말이 청산유수다 or 청산유수처럼; can hint at a glib talker.
Related words