in·​fect | \ in-ˈfekt How to pronounce infect (audio) \
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 How to pronounce infector (audio) \ 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 The sites, which had thousands of visitors per week, would assess victim devices and then infect them, if possible, with powerful monitoring malware. Wired, "Apple Finally Breaks Its Silence on iOS Hacking Campaign," 6 Sep. 2019 Paranoia, propaganda, and PTSD are part of the proverbial sickness that infects the characters in season 10. Nick Romano,, "New The Walking Dead season 10 photos tease intense fights and new characters," 8 Aug. 2019 Hepatitis A is a virus that infects the liver and is spread through food, water and objects tainted by feces, or through close contact. Marcus Lim, Twin Cities, "Florida latest place to declare emergency over hepatitis A," 2 Aug. 2019 Does this scenario frighten you: A secret organization hacks into the city's computer system and infects it with a virus that shuts it down until its demands are met. Mark Lamster, Dallas News, "Data is shaping the future of Dallas, but be careful what you wish for," 1 Aug. 2019 Just as good times immunize a president, so too bad recessions infect him. Victor Davis Hanson, National Review, "The Economy, Father of Us All," 23 July 2019 Measles is a highly contagious disease that infected hundreds of thousands of children and killed an estimated 400 to 500 people every year until a vaccine was developed. Mercury News & East Bay Times Editorial Boards, The Mercury News, "Editorial: Governor must get on board with vaccinations bill," 9 June 2019 WannaCry took down millions of computers in 2017, using an unsophisticated yet pervasive attack that infected computers with ransomware. Mark Hachman, PCWorld, "NSA warns that 'BlueKeep' vulnerability in Windows XP and Windows 7 is especially dangerous," 5 June 2019 Their murders rock her so completely and infect her so much., "Author Gillian Flynn On Women Living In Fear & Sharp Objects' Female Rage," 6 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

26 Oct 2019

Time Traveler for infect

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

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More Definitions for infect


How to pronounce infect (audio)

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 How to pronounce infect (audio) \
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 How to pronounce infect (audio) \

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

Thesaurus: All synonyms and antonyms for 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

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