Dictionary.com
Thesaurus.com
Synonyms

musty

1 American  
[muhs-tee] / ˈmʌs ti /

adjective

mustier, mustiest
  1. having an odor or flavor suggestive of mold, as old buildings, long-closed rooms, or stale food.

    Synonyms:
    stale, moldy, dank
  2. obsolete; outdated; antiquated.

    musty laws.

  3. dull; apathetic.


musty 2 American  
[muhs-tee] / ˈmʌs ti /

noun

plural

musties
  1. (formerly) a kind of snuff having a musty flavor.


musty British  
/ ˈmʌstɪ /

adjective

  1. smelling or tasting old, stale, or mouldy

  2. old-fashioned, dull, or hackneyed

    musty ideas

"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

Other Word Forms

  • mustily adverb
  • mustiness noun

Etymology

Origin of musty1

1520–30; perhaps variant of moisty ( Middle English; see moist, -y 1) with loss of i before s as in master

Origin of musty2

First recorded in 1700–10; noun use of musty 1

Explanation

Use the word musty to describe an unclean, stale, and possibly moldy smell. If something smells musty that means it’s probably been sitting in a damp corner without any air for a little too long. Musty smells take time to develop: they’re caused by dampness and mold, and signal some amount of decay. You might also call the smell of a musty old basement rank or foul. But people also use musty to insult someone’s writing, or their ideas. A musty speech wouldn’t just be old-fashioned, it would be old in a bad way: rotten and boring.

Keep Reading on Vocabulary.com

Vocabulary lists containing musty

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

New research now shows that the distinctive musty scent of mummified remains holds valuable clues about how these elaborate burial rituals were carried out.

From Science Daily • Mar. 16, 2026

Edith Wharton is a moth-eaten gown in the musty attic of American literature.

From The Wall Street Journal • Feb. 5, 2026

The sharp tang of the tar and the musty, earthy smell of the observation pits meant a day of play and exploration.

From Los Angeles Times • Feb. 6, 2025

Although the troubles of our world never bled into “What We Do in the Shadows,” the story never shied away from politics within its own musty, rotten realm.

From Salon • Nov. 11, 2024

So they chewed on the musty bread and ate the onion.

From "Atonement" by Ian McEwan