#1 slaphappy s. [carefree, devil-may-care, freewheeling, happy-go-lucky, harum-scarum] cheerfully irresponsible; "carefree with his money"; "freewheeling urban youths"; "had a harum-scarum youth". wn #2 slaphappy s. [punch-drunk, silly] dazed from or as if from repeated blows; "knocked silly by the impact"; "slaphappy with exhaustion". wn