to play with (a toy, one's hair, etc.); to fiddle with
to toy with (one's emotions, etc.); to trifle with
to do with something as one pleases
to appreciate
猫がボールを弄ぶ姿が可愛らしかった。
The sight of the cat playing with a ball was adorable.
猫がテーブルの上のペンを弄んだ。
The cat played with the pen on the table.
彼は髪を弄びながら考え込んでいた。
He was lost in thought while fiddling with his hair.