dumb

American  

[duhm] / dʌm /

adjective

dumber, dumbest

1. lacking intelligence or good judgment; stupid; dull-witted.

2. lacking the power of speech (offensive when applied to humans).

   a dumb animal.

3. temporarily unable to speak.

   dumb with astonishment.

4. refraining from any or much speech; silent.

5. made, done, etc., without speech.

6. lacking some usual property, characteristic, etc.

7. performed in pantomime; mimed.

8. Computers. pertaining to the inability to do processing locally.

   A dumb terminal can input, output, and display data, but cannot process it.

9. Nautical.

   1. (of a barge) without means of propulsion.

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

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verb phrase

1. dumb down to make or become less intellectual, simpler, or less sophisticated.

   to dumb down a textbook; American movies have dumbed down.

dumb British  

/ dʌm /

adjective

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

3. temporarily lacking or bereft of the power to speak

   struck dumb

4. refraining from speech; uncommunicative

5. producing no sound; silent

   a dumb piano

6. made, done, or performed without speech

7. informal

   1. slow to understand; dim-witted

   2. foolish; stupid See also dumb down

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

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Sensitive Note

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 Word Forms

Derived Forms

• quasi-dumb
  adjective
• dumbly
  adverb
• dumbness
  noun
• quasi-dumbly
  adverb

Etymology

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

Explanation

Today, most of the time someone or something is described as dumb when it shows a lack of thought, like your dumb idea of wearing flip-flops in a snowstorm. Dumb is the Old English word that means "mute, speechless," and itself came from an even older word dheubh meaning "confusion, stupefaction, dizziness." Today, dumb still means "unable to speak," but it doesn't have anything to do with intelligence. Its other meaning, however, does. If you make a dumb mistake, it's something you could have avoided if you thought it through first.

Example Sentences

Markwayne Mullin has a brilliantly dumb idea he’s workshopping.

From Slate • May 30, 2026

As an actor who had to be exceedingly smart to play dumb blondes, she used the shoot to make “a profound statement about her social positioning.”

From Los Angeles Times • May 25, 2026

In the IPO paperwork, the company formally defines “The Algorithm” as a five-step process with the guiding principles of SpaceX: make less dumb, delete, optimize, accelerate, automate.

From The Wall Street Journal • May 22, 2026

Spreads are often derided since profits are limited to the difference between strike prices, less the cost, but that’s dumb.

From Barron's • May 13, 2026

There are a million of the dumb things on this campus.

From "Glitch" by Laura Martin

Related Words

• dull
• foolish