- carefree, devil-may-care, freewheeling, happy-go-lucky, harum-scarum, slaphappy - cheerfully irresponsible; "carefree with his money"; "freewheeling urban youths"; "had a harum-scarum youth"
Antonym: responsible (indirect, via irresponsible)
- punch-drunk, silly, slaphappy - dazed from or as if from repeated blows; "knocked silly by the impact"; "slaphappy with exhaustion"
Antonyms: clearheaded, clear-thinking (indirect, via confused)