to be playful; to gambol; to be amused (with something); to play; to sport; to frolic; to joke
to flirt with
「戯れる」 has another reading with different meanings.
詩人は想像の世界で戯れている。
The poet plays in a world of imagination.
彼は言葉で人をからかうように戯れた。
He played with people by teasing them with words.
子どもたちが砂浜で戯れる姿が微笑ましかった。
It was heartwarming to see the children frolicking on the sandy beach.