SLAPHAPPIEST
Scrabble letter values: S1L1A1P3H4A1P3P3I1E1S1T1 = 21
Definition
SLAPHAPPIEST is the superlative of SLAPHAPPY.
adjective SLAPHAPPY: cheerfully irresponsible.
Synonyms of SLAPHAPPY: carefree, devil-may-care, freewheeling, happy-go-lucky, harum-scarum