infects; infected; infecting
1
: to cause (someone or something) to become sick or affected by disease
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.
—often used as (be) infectedHe was infected by a coworker.
He was infected with AIDS.
2
a
: to cause (someone) to feel an emotion
—usually + with
She has infected everyone with her enthusiasm. [=her enthusiasm has made other people feel enthusiastic too]
b
of an emotion
: to spread to (other people)
Her enthusiasm has infected everyone.
3
of a computer virus
: to cause (a computer or computer file) to stop working as it should
The virus has infected many computers.
All the computers in the office were infected by/with the same virus.
Cite this Entry
“Infect.” Merriam-Webster.com Simple Definition, Merriam-Webster, https://www.merriam-webster.com/simple/infect. Accessed 24 Jun. 2026.
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