From WordNet (r) 3.0 (2006):
silly
adj 1: ludicrous, foolish; "gave me a cockamamie reason for not
going"; "wore a goofy hat"; "a silly idea"; "some wacky
plan for selling more books" [syn: cockamamie,
cockamamy, goofy, sappy, silly, wacky,
whacky, zany]
2: lacking seriousness; given to frivolity; "a dizzy blonde";
"light-headed teenagers"; "silly giggles" [syn: airheaded,
dizzy, empty-headed, featherbrained, giddy, light-
headed, lightheaded, silly]
3: inspiring scornful pity; "how silly an ardent and
unsuccessful wooer can be especially if he is getting on in
years"- Dashiell Hammett [syn: pathetic, ridiculous,
silly]
4: dazed from or as if from repeated blows; "knocked silly by
the impact"; "slaphappy with exhaustion" [syn: punch-drunk,
silly, slaphappy]
n 1: a word used for misbehaving children; "don't be a silly"