in·fect | \in-ˈfekt \
infected; infecting; infects

Definition of infect 

transitive verb

1 : to contaminate with a disease-producing substance or agent (such as bacteria)

2a : to communicate a pathogen or a disease to

b of a pathogenic organism : to invade (an individual or organ) usually by penetration

c of a computer virus : to become transmitted and copied to (a device, such as a computer)

3a : contaminate, corrupt the inflated writing that infects such stories

b : to work upon or seize upon so as to induce sympathy, belief, or support trying to infect their salespeople with their enthusiasm

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Other Words from infect

infector \in-ˈfek-tər \ noun

Examples of infect in a Sentence

If you're sick you should stay home to avoid infecting other people in the office. The virus has infected many people. They were unable to prevent bacteria from infecting the wound. Her enthusiasm has infected everyone. The virus has infected many computers. All the computers in the office were infected by the same virus.
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Recent Examples on the Web

More than 700 people were infected, 179 were left with permanent brain and kidney damage, and four children died. Emily Atkin, The New Republic, "America’s Enduring Failure to Prevent Food-Borne Illness," 9 July 2018 Through small jabs and takedowns, my dad has ensured the scars from his abuse have stayed open, oozing and infected, making healing impossible. Brian Gresko, Longreads, "Wrestling With My Father," 12 June 2018 To name a kind of attraction after a disease carried by mosquitoes that killed one out of four people severely infected said something about the attraction. Weike Wang, The New Yorker, "Omakase," 6 June 2018 Norovirus spreads quickly and is found in the vomit or feces of those infected with the virus, according to the Centers for Disease Control and Prevention. Mike Nolan, Daily Southtown, "Food at Shedd not reason more than 100 Andrew High students got sick after prom: health officials," 11 May 2018 This paranoia has even infected my preferred activity: eating. Leah Bhabha, Vogue, "The Best New York Restaurants for a Bathroom Selfie," 14 Apr. 2018 This 2002 gross-out horror movie—about a flesh-eating disease infecting a bunch of horned-up twentysomethings on a weekend getaway—is most notable for two things. Joanna Robinson, HWD, "What’s New on Netflix in April," 21 Mar. 2018 More than 900 people were infected over 14 months before the government identified a meat-processing factory owned by Tiger Brands Ltd., the continent’s biggest packaged-food company, as the source. Paul Burkhardt,, "What’s Behind the Deadliest Outbreak of Listeriosis," 15 Mar. 2018 MacDonald described a crop that was infected with powdery mildew from the beginning and later was infested with spider mites and other pests. Michael Dresser, Washington Post, "Regulators investigate Maryland medical marijuana grower for alleged pesticide use," 10 July 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'infect.' 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 infect

14th century, in the meaning defined at sense 2a

History and Etymology for infect

Middle English, from Latin infectus, past participle of inficere, from in- + facere to make, do — more at do

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Statistics for infect

Last Updated

12 Oct 2018

Look-up Popularity

Time Traveler for infect

The first known use of infect was in the 14th century

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More Definitions for infect



English Language Learners Definition of infect

: to cause (someone or something) to become sick or affected by disease

: to cause (someone) to feel an emotion

of an emotion : to spread to (other people)


in·fect | \in-ˈfekt \
infected; infecting

Kids Definition of infect

1 : to pass on or introduce a germ, illness, or disease to : to cause sickness in Don't infect me with your cold. The bacteria can infect wounds.

2 : to cause to share similar feelings Her enthusiasm infects the other players.

in·fect | \in-ˈfekt \

Medical Definition of infect 

1 : to contaminate with a disease-producing substance or agent (as bacteria)

2a : to communicate a pathogen or a disease to

b of a pathogenic organism : to invade (an individual or organ) usually by penetration — compare infest

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Comments on infect

What made you want to look up infect? Please tell us where you read or heard it (including the quote, if possible).


to teach someone the beliefs of a group

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