Skilled; proficient; good at something (describes someone or their ability).
彼はピアノが上手だ。
He is good at the piano.
上手に説明して、皆が理解できた。
She explained it skillfully, and everyone could understand.
絵を描くのが上手な友達にコツを聞いた。
I asked my friend who is good at drawing for tips.
日本語が上手になるには毎日練習することだ。
To become good at Japanese, you should practice every day.
Flattery (archaic or rare usage).
彼女は上手に褒めて、相手の気を引いた。
She flattered him skillfully and caught his attention.