silliness

UK: /ˈsɪlinɪs/

WordReference Random House Learner's Dictionary of American English © 2025

sil•ly /ˈsɪli/   adj., -li•er, -li•est, n., pl. -lies. 
adj. 

1. lacking good sense;
   foolish:
   called him a silly young fool.
2. absurd;
   ridiculous;
   nonsensical:
   filled with silly ideas.
3. stunned;
   dazed:
   He knocked me silly.

n. [countable]

4. Informal Terms a silly or foolish person.

sil•li•ness, n. [uncountable]

WordReference Random House Unabridged Dictionary of American English © 2025

sil•ly  (sil′ē), adj., -li•er, -li•est, n., pl. -lies. 
adj. 

1. weak-minded or lacking good sense;
   stupid or foolish:
   a silly writer.
2. absurd;
   ridiculous;
   irrational:
   a silly idea.
3. stunned;
   dazed:
   He knocked me silly.
4. [Cricket.] (of a fielder or the fielder's playing position) extremely close to the batsman's wicket:
   silly mid off.
5. [Archaic.] rustic;
   plain;
   homely.
6. [Archaic.] weak;
   helpless.
7. [Obs.] lowly in rank or state;
   humble.

n. 

8. Informal Terms a silly or foolish person:
   Don't be such a silly.

• 1375–1425; earlier sylie, sillie foolish, feeble-minded, simple, pitiful; late Middle English syly, variant of sely seely

sil′li•ly, adv. 
sil′li•ness, n. 
Synonyms

• 1. witless, senseless, dull-witted, dim-witted. See foolish. 
• 2. inane, asinine, nonsensical, preposterous.

Antonyms

• 1. sensible.