Dumb
Speechless
Synonyms: Speechless, wordless, at a loss for words, inarticulate, uncommunicative, tight-lipped, saying nothing, tongue-tied, silent, voiceless, taciturn, untalkative, close-mouthed, and mum.
Mute
Synonyms: Mute, without the power of speech, aphonic, unable to speak, aphasic, and dumb.
Stupid
Synonyms: Stupid, ignorant, brainless, foolish, slow, dull-witted, half-witted, doltish, simple, empty-headed, vapid, moronic, cretinous, bovine, thick, dopey, dozy, slow on the uptake, thickheaded, dunderheaded, fat-headed, muttonheaded, lamebrained, pea-brained, dead from the neck up, not the full shilling, dof, unintelligent, dense, mindless, slow-witted, dull, witless, blockish, dunce-like, simple-minded, vacuous, idiotic, imbecilic, obtuse, lumpish, dim, dippy, half-baked, soft in the head, chuckleheaded, wooden-headed, thick-skulled, boneheaded, birdbrained, brain-dead, daft, as thick as two short planks, and dotish.
Example Sentences
That was a dumb idea.
He felt dumb after losing.
Don't make dumb decisions today.
The joke was really dumb.