1.
selfish, doing as one pleases, self-indulgent
Acting according to one's own desires without considering others. Always carries a negative nuance of selfishness or inconsiderate behavior.
Usage
Used as a な-adjective (好き勝手な + noun) or adverbially (好き勝手に + verb). Always negative — it implies the person is being inconsiderate or disregarding rules and others' feelings.
Common patterns
Similar words
勝手 alone can mean "selfish" or "at one's convenience." 好き勝手 intensifies this by adding 好き (liking), emphasizing that the person is doing exactly what they want.
Related Words
Compare:
思うがまま (as one wishes)