This is the 3582nd most frequent Japanese word.
賢
"賢" means "wise" or "virtuous."
In this sentence, '賢い' is used as an adjective to describe someone's intelligence or wisdom.
彼は非常に賢い人だ。
He is a very intelligent person.
Here, '賢者' functions as a noun, indicating a wise person or sage.
賢者は自分の過ちを認める。
A wise man admits his mistakes.
The word '賢明' is used as an adjective meaning wise or prudent, describing the quality of the idea.