List of dumb synonyms and dumb related words.
Boeotian, abiotic, anaudic, animal, animalian, animalic, animalistic, aphasic, aphonic, apish, asinine, awkward, azoic, batty, beastlike, beastly, beef-brained, beef-witted, befooled, beguiled, besotted, bestial, blankminded, blockheaded, blockish, bovine, brainless, breathless, brief, brusque, brutal, brute, brutelike, brutish, buffoonish, callow, chumpish, cloddish, close, close-tongued, closemouthed, cockeyed, concise, cowish, crass, crazy, credulous, curt, daffy, daft, dazed, dense, dizzy, doltish, doting, dull, dullard, dumbfounded, dumbstricken, dumbstruck, duncical, duncish, economical of words, empty, empty-headed, exanimate, fat, fatheaded, fatuitous, fatuous, flaky, fond, fool, foolheaded, foolish, fuddled, futile, gaga, gauche, goofy, green, groping, gross, gulled, idiotic, ignorant, imbecile, inane, inanimate, inanimated, inarticulate, incoherent, indisposed to talk, indistinct, ineducable, inept, inert, inexperienced, infatuated, innocent, insane, insensate, insensible, insentient, instinctive, instinctual, klutzy, know-nothing, kooky, laconic, lifeless, loony, lumpish, mad, maudlin, maundering, mindless, moronic, mum, mute, naive, nescient, nonconscious, nonliving, nonrational, numskulled, nutty, oafish, opaque, quiet, raw, reticent, sappy, screwy, senseless, sentimental, short, silent, silly, simple, snug, sottish, soulless, sparing of words, speechless, strange to, stricken dumb, stupid, subhuman, taciturn, tentative, terse, thick, thick-witted, thoughtless, tight-lipped, tongue-tied, tongueless, unacquainted, unanimated, unapprized, uncommunicative, uncomprehending, unconscious, unconversant, unenlightened, unfamiliar, unfeeling, unilluminated, uninformed, uninitiated, unintelligent, unknowing, unloquacious, unposted, unripe, unsure, untalkative, unteachable, unversed, vacuous, voiceless, wacky, wet, witless, word-bound, wordless, wrongheaded, zoic, zooidal, zoologic