Synonyms for Slaphappy (same or very similar meaning)
WordNet sense 1 (cheerfully irresponsible):
carefree, devil-may-care, freewheeling, happy-go-lucky, harum-scarum
WordNet sense 2 (showing lack of care for consequences):
irresponsible
WordNet sense 3 (dazed from or as if from repeated blows):
punch-drunk, silly
WordNet sense 4 (mentally confused; unable to think with clarity or act intelligently):
confused
From the ODE community, based on WordNet
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