in·​fest | \ in-ˈfest How to pronounce infest (audio) \
infested; infesting; infests

Definition of infest

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

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Other Words from infest

infestant \ in-​ˈfe-​stənt How to pronounce infestant (audio) \ noun
infestation \ ˌin-​ˌfe-​ˈstā-​shən How to pronounce infestation (audio) \ noun
infester \ in-​ˈfe-​stər How to pronounce infester (audio) \ noun

Synonyms for infest


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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 John Park, president and CEO of a national food chain, was charged with violating the Food, Drug and Cosmetic Act for allowing food to be shipped from company warehouses infested with rats. Todd Haugh, The Conversation, "Coronavirus impact: Meat processing plants weigh risks of prosecution if they’re blamed for spreading infection," 27 Apr. 2020 Investigators unsuccessfully squeezed Caputo for proof that Trump’s campaign was infested with Kremlin operatives. Deroy Murdock, National Review, "A Patriot and a Professional," 17 Apr. 2020 In areas of the Illinois and Kentucky rivers that are heavily infested with Asian carp, native fish populations have declined significantly. Paul A. Smith, Milwaukee Journal Sentinel, "Catch of 51 Asian carp in Mississippi River near La Crosse is largest in Wisconsin or Minnesota waters," 13 Mar. 2020 The 24-year-old rapper continues to celebrate his hometown pride in the music video, which shows off the Bronx being infested with Joker look-alikes. Heran Mamo, Billboard, "Here Are the Lyrics to A Boogie Wit Da Hoodie's 'King of My City'," 12 Feb. 2020 In each of the last five years, Baltimore has endured at least 300 homicides and municipal government has long been infested with corruption. Rainer Sabin, Detroit Free Press, "Inside the Baltimore superpower fueling Michigan football's 2020 recruiting class," 17 Dec. 2019 Beyond its isolation, the wing is infested with rodents and cockroaches, and inmates often have to navigate standing water — as well as urine and fecal matter — that spills from faulty plumbing, accounts from former inmates and lawyers said. Ali Watkins, New York Times, "Inmate 76318-054: The Last Days of Jeffrey Epstein," 17 Aug. 2019 Flea and tick collars are impregnated with chemicals that prevent the parasites from infesting your dog. The Editors, Field & Stream, "Nine Ways to Protect Your Dog from Ticks and Fleas," 3 Mar. 2020 If resident Canada geese infest the lawns and sidewalks of a local business and the Illinois DNR initiates a cull, Avery will take that goose meat to a pantry. Joe Genzel, Outdoor Life, "The Wild Game State Agencies Confiscate Does Not Go in a Dumpster," 10 Feb. 2020

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'infest.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of infest

1602, in the meaning defined at sense 1

History and Etymology for infest

French infester, from Latin infestare, from infestus hostile

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Time Traveler for infest

Time Traveler

The first known use of infest was in 1602

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Statistics for infest

Last Updated

2 May 2020

Cite this Entry

“Infest.” Dictionary, Merriam-Webster, Accessed 28 May. 2020.

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More Definitions for infest


How to pronounce infest (audio)

English Language Learners Definition of infest

of something harmful or unwanted : to be in or over (a place, an animal, etc.) in large numbers


in·​fest | \ in-ˈfest How to pronounce infest (audio) \
infested; infesting

Kids Definition of infest

: to spread or swarm in or over in a harmful manner Termites infested the tree.
in·​fest | \ in-ˈfest How to pronounce infest (audio) \

Medical Definition of infest

: to live in or on as a parasite the flea that infests cats horses infested with worms — compare infect

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More from Merriam-Webster on infest

Thesaurus: All synonyms and antonyms for infest

Spanish Central: Translation of infest

Nglish: Translation of infest for Spanish Speakers

Britannica English: Translation of infest for Arabic Speakers

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