[ duhm ]
See synonyms for: dumbdumberdumbestdumbly on Thesaurus.com

adjective,dumb·er, dumb·est.
  1. lacking intelligence or good judgment; stupid; dull-witted.

  2. lacking the power of speech (offensive when applied to humans): a dumb animal.

  1. temporarily unable to speak: dumb with astonishment.

  2. refraining from any or much speech; silent.

  3. made, done, etc., without speech.

  4. lacking some usual property, characteristic, etc.

  5. performed in pantomime; mimed.

  6. Computers. pertaining to the inability to do processing locally: A dumb terminal can input, output, and display data, but cannot process it.: Compare intelligent (def. 4).

  7. Nautical.

    • (of a barge) without means of propulsion.

    • (of any craft) without means of propulsion, steering, or signaling.

Verb Phrases
  1. dumb down, Informal. to make or become less intellectual, simpler, or less sophisticated: to dumb down a textbook; American movies have dumbed down.

Origin of dumb

First recorded before 1000; Old English; cognate with Old Norse dumbr, Gothic dumbs, Old Saxon dumb, Old High German tump, German dumm

usage note For dumb

Dumb in the sense “lacking the power of speech” is perceived as insulting when describing humans (but not animals), probably because dumb also means “stupid; dull-witted.” The noun dummy in the sense “person who lacks the power of speech” is also perceived as insulting, as are the terms deaf-and-dumb, deaf-mute, and mute. The adjective hard of hearing is acceptable though not the term of choice, partly because it lacks directness. The preferred term is deaf, which makes no reference to an inability to speak or communicate; the capitalized word Deaf signals membership in this community.

Other words from dumb

  • dumb·ly, adverb
  • dumb·ness, noun
  • qua·si-dumb, adjective
  • qua·si-dumb·ly, adverb

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use dumb in a sentence

  • He can get away with faking, but the dumbest jury in the world would know what receiving stolen goods was, and he knows it.

    Murder in the Gunroom | Henry Beam Piper
  • He is the dumbest kind of a dumb fool that ain't king in some little corner.

    Rolf In The Woods | Ernest Thompson Seton
  • He's always been considered the dumbest one in all our relations—never did know how to act.

    Seventeen | Booth Tarkington
  • "The dumbest, woodenest, most conscientious young female person it has ever been my lot to meet," goes on Mr. Mills.

    Torchy, Private Sec. | Sewell Ford
  • I supposed that eventually they'd pick the dumbest day laborer in the place and make him the patsy.

    Four-Day Planet | Henry Beam Piper

British Dictionary definitions for dumb


/ (dʌm) /

  1. lacking the power to speak, either because of defects in the vocal organs or because of hereditary deafness

  2. lacking the power of human speech: dumb animals

  1. temporarily lacking or bereft of the power to speak: struck dumb

  2. refraining from speech; uncommunicative

  3. producing no sound; silent: a dumb piano

  4. made, done, or performed without speech

  5. informal

    • slow to understand; dim-witted

    • foolish; stupid: See also dumb down

  6. (of a projectile or bomb) not guided to its target

Origin of dumb

Old English; related to Old Norse dumbr, Gothic dumbs, Old High German tump

Derived forms of dumb

  • dumbly, adverb
  • dumbness, noun

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012