infest

verb

in·​fest in-ˈfest How to pronounce infest (audio)
infested; infesting; infests
Synonyms of infestnext

transitive verb

1
: to spread or swarm in or over in a troublesome manner
a slum infested with crime
shark-infested waters
2
: to live in or on as a parasite
infestant
in-ˈfe-stənt How to pronounce infest (audio)
noun
infestation
ˌin-ˌfe-ˈstā-shən How to pronounce infest (audio)
noun
infester
in-ˈfe-stər How to pronounce infest (audio)
noun

Synonyms

See All Synonyms & Antonyms in Thesaurus

Examples of infest in a Sentence

in desperation, we called in an exterminator because the house was infested with ants
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Frustrated by delays in federal and state deterrence projects, and annoyed by their own encounters with the flying fish, residents of a small town in west Illinois saw both a challenge and an opportunity in the large numbers of silver carp that infested their stretch of the Illinois River. — Adriana Pérez, Chicago Tribune, 10 Feb. 2025 Ana Miller, an organizer at HAND, shared her experience as someone who has experienced homelessness, saying some shelters are infested with pests. — Megan Ulu-Lani Boyanton, The Denver Post, 26 Feb. 2025 Back then, the Eagles’ home, Veterans Stadium, was infested with rats and falling apart. — Justin Birnbaum, Forbes, 7 Feb. 2025 Ten workers lived in one small home, officials said, and the house was infested with bed bugs and cockroaches. — Kate Linderman, Kansas City Star, 5 Feb. 2025 See All Example Sentences for infest

Word History

Etymology

French infester, from Latin infestare, from infestus hostile

First Known Use

1602, in the meaning defined at sense 1

Time Traveler
The first known use of infest was in 1602

Rhymes for infest

See All Rhymes for infest

Browse Nearby Words

infest
See all Nearby Words

Cite this Entry

“Infest.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/infest. Accessed 23 Mar. 2025.

Copy Citation

Share

Kids Definition

infest

verb
in·​fest in-ˈfest How to pronounce infest (audio)
1
: to spread or swarm in or over in a troublesome manner
a neighborhood infested with crime
shark-infested waters
2
: to live in or on as a parasite
horses infested with worms
infestation
ˌin-ˌfes-ˈtā-shən How to pronounce infest (audio)
noun

Medical Definition

infest

transitive verb
in·​fest in-ˈfest How to pronounce infest (audio)
: to live in or on as a parasite
the flea that infests cats
horses infested with worms
compare infect

More from Merriam-Webster on infest

Nglish: Translation of infest for Spanish Speakers

Last Updated: - Updated example sentences
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!

Popular in Grammar & Usage

See More

The Difference Between 'i.e.' and 'e.g.'

How to Use Em Dashes (—), En Dashes (–) , and Hyphens (-)

Why is '-ed' sometimes pronounced at the end of a word?

What's the difference between 'fascism' and 'socialism'?

More Commonly Misspelled Words
See More

Popular in Wordplay

See More

What do SCOTUS, POTUS, and FLOTUS mean?

Flower Etymologies For Your Spring Garden

More Words with Remarkable Origins

Terroir, Oenophile, & Magnum: Ten Words About Wine

8 Words for Lesser-Known Musical Instruments
See More

Popular Features

See More

The Difference Between 'i.e.' and 'e.g.'

What do SCOTUS, POTUS, and FLOTUS mean?

Flower Etymologies For Your Spring Garden
See More

Games & Quizzes

See All
Play Quordle: Guess all four words in a limited number of tries. Each of your guesses must be a real 5-letter word.
Quordle Can you solve 4 words at once?
Play Blossom: Solve today's spelling word game by finding as many words as you can using just 7 letters. Longer words score more points.
Blossom Word Game Pick the best words!
Play Missing Letter: a crossword with a twist. Each of the 25 puzzle words start with a different letter of the alphabet. Which letter is missing?
Missing Letter A daily crossword with a twist
dog-in-disguise
Rhyme Disguise Quiz Pair up words that look different but sound alike.
See All