infect

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verb in·fect \in-ˈfekt\

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 tob of a pathogenic organism : to invade (an individual or organ) usually by penetrationc 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 storiesb : to work upon or seize upon so as to induce sympathy, belief, or support trying to infect their salespeople with their enthusiasm

infector

play \in-ˈfek-tər\ noun

See infect defined for English-language learners

See infect defined for kids

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.

Recent Examples of infect from the Web

Indian television, in particular, has been infected by a style of hyperbolic ranting that makes some debate programmes hard to watch.

— The Economist, "The elephant in its labyrinthIn the race with its tricky neighbour, India has recently been winning," 22 July 2017
Almost all dogs exposed to the virus are infected and about 80 percent develop flu symptoms.

— darcy costello, The Courier-Journal, "Highly contagious dog flu outbreak reaches Louisville Metro Animal Services," 14 July 2017
Mom's new boyfriend infects her, turns her into a stinging monstrosity, Dad kills her.

— carmel carrillo, chicagotribune.com, "'The Walking Dead's' Carl vs. 'The Strain's' Zack: character smackdown," 12 July 2017
The illness, which is spread by the Lone Star tick, typically infects people from May to September, and requires hospitalization.

— jessica mattern, Country Living, "New Tick-Borne "Heartland Virus" Is Spreading Across the South," 10 July 2017
Introducing the genome into cells infected with a different type of poxvirus led these cells to start producing infectious horsepox virus particles, a technique first shown to work in a 2002 paper in PNAS.

— kai kupferschmidt, Science | AAAS, "How Canadian researchers built a poxvirus for $100,000 using mail-order DNA," 6 July 2017
On May 11, the Ministry of Health of the Democratic Republic of the Congo (DRC) notified the World Health Organization that one of its citizens had been infected with the Ebola virus.

— ed yong, The Atlantic, "How the Democratic Republic of the Congo Beat Ebola In 42 Days," 3 July 2017
Even for those who are not in danger of liver failure or cancer in the short term, the virus can cause emotional duress and worries about infecting others.

— the washington post, NOLA.com, "Louisiana considers radical step to counter high drug prices: Federal intervention," 3 July 2017
In the same vein, Dr. Nazarian suggests to follow up the cleanse with Aquaphor to prevent the cut from getting infected.

— alanna martine kilkeary, Teen Vogue, "How to Shave Your Pubic Area Safely," 2 July 2017

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.

Origin and Etymology of infect

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

NEW! Time Traveler

First Known Use: 14th century

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INFECT Defined for English Language Learners

infect

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verb

Definition of infect for English Language Learners

: 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)

INFECT Defined for Kids

infect

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verb in·fect \in-ˈfekt\

Definition of infect for Students

infected

;

infecting

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.

Medical Dictionary

infect

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transitive verb 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 tobof a pathogenic organism : to invade (an individual or organ) usually by penetration—compare infest