noun, na-adjective
selfish; self-indulgent; doing as one pleases
Describes acting freely without regard for others, often with a negative connotation of selfishness. Can be used as a noun or na-adjective.
彼は好き勝手に振る舞って、周りを困らせている。
He behaves selfishly and causes trouble for those around him.
好き勝手なことばかり
Please stop saying only selfish things.
わがまま is more about personal selfishness or willfulness, while 好き勝手 emphasizes acting freely without considering others, often in a more active or disruptive way.
自分勝手 is very similar, meaning self-centered or selfish, but 好き勝手 can also imply doing whatever one likes without restraint, not necessarily always negative.
Compound of 好き (like, preference) and 勝手 (one's own convenience, selfishness). The combination reinforces the idea of acting solely according to one's own desires.