Another word for silly
senseless, ridiculous, nonsensical, foolish, fatuous, unreasonable, irrational, stupid, asinine, absurd, simpleminded, harebrained, brainless, featherbrained, empty-headed, vacuous, muddleheaded, illogical, ludicrous, preposterous, inane, giddy, frivolous, trivial, shallow, puerile, birdbrained*, air-headed*, dippy*, ditzy*, sappy*, goofy*.
silly implies ridiculous or irrational behavior that demonstrates a lack of common sense, good judgment, or sobriety it was silly of you to dress so lightly; stupid implies a slow-wittedness or lack of normal intelligence he is stupid to believe that; fatuous suggests stupidity, inanity, or obtuseness coupled with a smug complacency a fatuous smile; asinine implies the extreme stupidity conventionally attributed to an ass an asinine argument See also syn. study at absurd.
Another word for sillyadjective
Displaying a complete lack of forethought and good sense:brainless, fatuous, foolish, insensate, mindless, senseless, unintelligent, weak-minded, witless. See ability, planned
So senseless as to be laughable:absurd, foolish, harebrained, idiotic, imbecilic, insane, lunatic, mad, moronic, nonsensical, preposterous, softheaded, tomfool, unearthly, zany. (Informal) cockeyed, crazy, loony, loopy. (Slang) balmy2, dippy, dopey, jerky, sappy, wacky. See ability, knowledge
Given to lighthearted silliness:empty-headed, featherbrained, flighty, frivolous, frothy, giddy, harebrained, lighthearted, scatterbrained. (Informal) gaga. (Slang) birdbrained, dizzy. See ability