weak-minded or lacking good sense; stupid or foolish

a silly writer.

absurd; ridiculous; irrational

a silly idea.

stunned; dazed

He knocked me silly.

Cricket . (of a fielder or the fielder's playing position) extremely close to the batsman's wicket

silly mid off.

Archaic . rustic; plain; homely.

Archaic . weak; helpless.

Obsolete . lowly in rank or state; humble.

Informal . a silly or foolish person

Don't be such a silly.

adjective

mature , mundane , practical , sensible , serious , wise

adjective

asinine , balmy , brainless , childish , crazy , dippy , dizzy * , empty , empty-headed * , fatuous , featherbrained * , flighty , foolhardy , frivolous , harebrained * , idiotic , ignorant , illogical , immature , imprudent , inane , inappropriate , inconsistent , irrational , irresponsible , ludicrous , meaningless , muddle-headed , nitwitted , nonsensical , pointless , preposterous , puerile , ridiculous , senseless , sheepheaded , simple , simpleminded , stupid , unintelligent , unreasonable , unwise , vacuous , witless , foolish , insensate , weak-minded , absurd , harebrained , imbecilic , insane , lunatic , mad , moronic , softheaded , tomfool , unearthly , zany , empty-headed , featherbrained , frothy , lighthearted , scatterbrained , childlike , cuckoo , daft , dazed , dumb , foppish , funny , giddy , goofy , half-witted , imbecile , inept , loopy , shallow , simpleton , wacky