infect

verb

in·​fect in-ˈfekt How to pronounce infect (audio)
infected; infecting; infects

transitive verb

1
: to contaminate with a disease-producing substance or agent (such as bacteria)
2
a
: 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)
3
a
: 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
infector 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.
Recent Examples on the Web The measles virus can stay in the air and infect others for up to two hours after a contagious person has left the room. Discover Magazine, 8 Mar. 2024 The iPSCs could be a good way to figure out how the virus infects different cell types. Matt Reynolds, WIRED, 6 Mar. 2024 Compounding the impact, thousands of organizations cut off Change Health from their systems to ensure the hackers did not infect their networks as well. Democrat-Gazette Staff and Wire Reports, arkansasonline.com, 2 Mar. 2024 While the new guidance unifies the CDC’s advice on what to do when one is infected with a respiratory illness, the 25-page document highlights one important exclusion: measles. Helen Branswell, STAT, 1 Mar. 2024 The illness is most detrimental in children under 5 years of age and older adults, though the CDC estimates as many as 19 to 21 million people are infected each year. Mary Whitfill Roeloffs, Forbes, 1 Mar. 2024 That is different than in 2018 and 2019, when those countries saw many unvaccinated older children and adults infected too. Alexander Tin, CBS News, 1 Mar. 2024 Although you can still be infected after getting the vaccine, your illness would most likely be less aggressive and can be treated quicker. Ella Gonzales, Fort Worth Star-Telegram, 22 Feb. 2024 Hostile activity in cyberspace — from spying to the planting of malware to infect and disrupt a country's infrastructure — has become a hallmark of modern geopolitical rivalry. Colleen Long, Quartz, 21 Feb. 2024

These examples are programmatically compiled from various online sources to illustrate current usage of the word 'infect.' Any opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback about these examples.

Word History

Etymology

Middle English infecten, enfecten "to inflict with disease, pollute, damage, corrupt," borrowed from Latin infectus, past participle of inficere "to dye, discolor, impregnate, taint, contaminate with disease," from in- in- entry 2 + facere "to make, bring about, perform, do" — more at fact

First Known Use

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

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

Dictionary Entries Near infect

Cite this Entry

“Infect.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/infect. Accessed 19 Mar. 2024.

Kids Definition

infect

verb
in·​fect in-ˈfekt How to pronounce infect (audio)
1
: to contaminate with a disease-producing substance or germ
infected bedding
2
a
: to pass a germ or disease to
coughing people who infect others
b
: to enter and cause disease in
bacteria that infect wounds
c
: to become copied to
a virus has infected the computer
3
: to cause to share one's feelings
infected everyone with his enthusiasm
infector noun

Medical Definition

infect

transitive verb
in·​fect in-ˈfekt How to pronounce infect (audio)
1
: to contaminate with a disease-producing substance or agent (as bacteria)
2
a
: to communicate a pathogen or a disease to
b
of a pathogenic organism : to invade (an individual or organ) usually by penetration compare infest
Last Updated: - Updated example sentences
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