dudvsdumbWhich spelling fits?

Quick tell: dud is a noun, dumb is an adjective, so they fill different roles in a sentence.

Which to use

“dud” is a noun and “dumb” is an adjective - they look or sound alike but fill different roles in a sentence.

#29,251
“dud” frequency rank
#2,788
“dumb” frequency rank
32039
confusion score

Side-by-Side Comparison

Feature dud dumb
Definition A device or machine that is useless because it does not work properly or has failed to work, such as a bomb, or explosive projectile. Unable to speak; lacking power of speech.

Where the eye mixes dud and dumb

Muted = shared; highlighted = the visual trap. They share 2 letters in sequence.

3 ch
dud
4 ch
dumb

Visual trap between dud and dumb

These two trip readers on the page rather than in the ear: dud is /dʌd/ while dumb is /dʌm/. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 letter(s) in length, and the parts of speech differ too (noun vs adjective), which is usually the fastest check. Our composite confusion score for this pair is 32039, derived from the frequency rank of both members and their visual similarity.

dud is recorded at frequency rank #29,251, classified as anoun, pronounced /dʌd/. dumb is at rank #2,788, tagged as anadj, pronounced /dʌm/.

Glosses for this pair are partially populated in our dataset, but the full side-by-side definitions above should still guide you to the right choice.

With a confusion score of 32039, this pair ranks #341,117 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of dud vs dumb

Shared letters: du. Private to "dud": -. Private to "dumb": bm.

"dud" · 3 letters · shape CVC  ·  "dumb" · 4 letters · shape CVCC

Known mistypes of this pair

  • dumbddumb · dmub · dubm · dumbb · dummb · udmb

Frequently Asked Questions

Is swapping "dud" for "dumb" ever safe?
No - they are not even the same part of speech. "dud" is a noun and "dumb" an adjective, so a sentence built for one is usually ungrammatical with the other.
Which is more common, "dud" or "dumb"?
"dumb" is the more common of the two: it sits at frequency rank #2,788 in our English list, against #29,251 for "dud". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

Useful next steps

Eye-level mix-up between "dud" and "dumb" is sorted above. Next: full entries or other pairs that share a letter shape.

  • Full dictionary entry for "dud" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "dumb" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #341,117 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "dud" and "dumb" also get mixed up with nearby pairs, the highest-scored neighbour is "dox vs dud". Nearby pair
  • Recorded mistypes exist for at least one side of this pair, useful when a spell-checker or OCR lands on the wrong form. See mistypes

Confusion rank #341,117 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list