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

That outbreak affected Canada as well — infecting 42 people and killing one. Rachel Becker, The Verge, "Throw out your romaine, it could be contaminated with E. coli," 20 Nov. 2018 If your asparagus bed does become infected by disease organisms, your best option is to start a new bed in a distant part of the garden, using newly purchased or grown plants. The Editors, Good Housekeeping, "How to Grow Garden-Fresh Asparagus," 19 Aug. 2018 Worldwide, the bacteria infected 10.4 million people. Brett Molina, USA TODAY, "Tuberculosis scare forces evacuations at Johns Hopkins Hospital," 6 July 2018 New Jersey health officials say a second woman suspected of being infected with measles has been identified in South Jersey and may have exposed others in Burlington and Camden Counties. Rita Giordano,, "Second suspected measles case detected in South Jersey," 5 July 2018 His groin area became infected within weeks and had to be treated. Dave Altimari,, "Clinton Man Sues CVS For Giving Him Wrong Cream For His Groin," 23 June 2018 In court documents, Minkler alleges that Burkhart was a greedy, remorseless peddler of corruption who infected those around him. Arika Herron, Indianapolis Star, "Feds want former CEO of American Senior Communities to serve more than 12 years," 22 June 2018 Let’s hope, Kara, that this is a hopeful moment and this starts to infect ... Eric Johnson, Recode, "Tesla’s board is too weak to stop its CEO Elon Musk from tweeting," 5 Oct. 2018 One reason for market insouciance is that a crisis is unlikely to infect other economies: foreigners hold only around 30% of the government’s bonds these days. The Economist, "How Milan’s voters opted for the losers," 26 Apr. 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

7 Dec 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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More from Merriam-Webster on infect

Rhyming Dictionary: Words that rhyme with infect

Spanish Central: Translation of infect

Nglish: Translation of infect for Spanish Speakers

Britannica English: Translation of infect for Arabic Speakers

Comments on infect

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to enclose within walls

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