/slap"hap'ee/ , adj., slaphappier, slaphappiest . Informal.
1. severely befuddled; punch-drunk: a slaphappy boxer.
2. agreeably giddy or foolish: After a martini he was slaphappy.
3. cheerfully irresponsible: a slaphappy crowd.
[ 1935-40; SLAP 1 + HAPPY ]