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

Other Words from infest

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 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 It’s this ability to infest areas without large groups that make these invasive jumping worms so terrifying to the local environment. Joshua Hawkins, BGR, 5 Apr. 2022 But then scammers started to infest that market, offering fake codes and scamming players out of their money, leading some unsavvy players to think that Riot had cheated them. Kyle Orland, Ars Technica, 24 Mar. 2022 Those of us who infest cinemas may remember asking ourselves that uncomfortable question for the first time. The New Yorker, 25 Feb. 2022 What should gardeners do about the aphids and bugs that infest milkweed stems and blooms? Calvin Finch, San Antonio Express-News, 17 Sep. 2021 Villains from other realities infest the MCU, and Peter will have to capture them all. Chris Smith, BGR, 21 Nov. 2021 In addition to okra plantings, fire ants often infest container plantings. Calvin Finch, San Antonio Express-News, 17 Sep. 2021 The tiny orange critters infest plants that are too dry or whose leaves are covered in dust. Nan Sterman, San Diego Union-Tribune, 7 Aug. 2021 Silverfish are by far one of the most cursed insects that can infest your home—right next to cockroaches and centipedes. Kelly Allen, House Beautiful, 20 July 2021 See More

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.

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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Last Updated

13 Apr 2022

Cite this Entry

“Infest.” Dictionary, Merriam-Webster, Accessed 18 May. 2022.

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More Definitions for infest


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.


transitive verb
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

More from Merriam-Webster on infest

Nglish: Translation of infest for Spanish Speakers

Britannica English: Translation of infest for Arabic Speakers


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