[ in-fekt ]
/ ɪnˈfɛkt /
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See synonyms for: infect / infected / infecting on Thesaurus.com

verb (used with object)
verb (used without object)
to become infected.
Archaic. infected.
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Origin of infect

1350–1400; Middle English infecten<Latin infectus (past participle of inficere to immerse in dye, discolor, taint, poison), equivalent to in-in-2 + -fec-, combining form of facere to do1, make (see fact) + -tus past participle suffix



1. afflict, infect , inflict2. infect , infest, invest
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2021


What does infect mean?

Infect is a verb that means to taint someone or something with disease-causing germs or to spread a disease to another living thing, as in The doorknob was infected with disease-causing bacteria. 

Infect can also mean to taint something in a way that negatively affects quality, as in The water was infected with toxic chemicals. Computers and other devices that connect to the internet can also become infected. Instead of a virus of living organisms infecting your computer, though, bits of  code attack your computer system to do harm.

Infect is also used figuratively to mean to corrupt something in various ways. It can mean something was corrupted morally, as in The constant flattery caused him to be infected with hubris. 

Infect can also be used to mean someone has been corrupted by harmful thoughts or beliefs, as in He allowed hatred to infect his mind. 

The adjective infectious is used to mean something is capable of infecting things, as in Doctors worked to stop the spread of the infectious disease. 

Infect can be confused with infest, which means to overrun a place or live there in an unwanted manner.

Example: Tia stayed home from school so she wouldn’t infect her classmates with the flu. 

Where does infect come from?

The first records of the word infect come from around 1350. It ultimately comes from the Latin inficere, meaning “to immerse in dye” or “to taint.” Infect, according to any of its meanings, refers to tainting something or someone.

You will hear the word infect often used during outbreaks of disease or during flu season. Microorganisms that cause disease, such as bacteria and viruses, usually reproduce very quickly and are able to spread from one living thing to another. Often, this spread happens when bodily fluids make contact with surfaces and infect them with germs. A healthy person then touches this surface and the germs enter their body and infect them as well. For this reason, medical experts advise practices such as social distancing, cleanliness, and frequent handwashing to try and prevent being infected with a disease.

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What are some other forms related to infect?

  • infectant (adjective)
  • infectedness (noun)
  • infector (noun)
  • noninfected (adjective)

What are some synonyms for infect?

What are some words that share a root or word element with infect

What are some words that often get used in discussing infect?

What are some words infect may be commonly confused with?

How is infect used in real life?

Infect is a common word that most often refers to the spread of disease or disease-causing germs.

Try using infect!

Is infect used correctly in the following sentence?

I tried to stay in my room when I had the flu so that I wouldn’t infect my family with the flu virus.

How to use infect in a sentence

British Dictionary definitions for infect

/ (ɪnˈfɛkt) /

verb (mainly tr)
archaic contaminated or polluted with or as if with a disease; infected

Derived forms of infect

infector or infecter, noun

Word Origin for infect

C14: from Latin inficere to dip into, stain, from facere to make
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Medical definitions for infect

[ ĭn-fĕkt ]

To contaminate with a pathogenic microorganism or agent.
To communicate a pathogen or disease to another organism.
To invade and produce infection in an organ or body part.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.