infected; infecting; infects
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
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
Many members also questioned the policy of vaccinating all babies, regardless of their risk or whether their mothers were infected.
—
Alice Park, Time, 6 Dec. 2025
About half of children with the disease were infected during birth, Children’s Hospital of Philadelphia said, while others caught it from family members.
—Cara Lynn Shultz, PEOPLE, 6 Dec. 2025
Infants and children who are infected with hepatitis B are more likely to develop chronic disease, including about 90% of infants and 30% of children ages 1 to 5.
—Brenda Goodman, CNN Money, 6 Dec. 2025
The rationale for giving the vaccine right away is to wipe out an infection that will afflict the majority of people who contract it as babies for the rest of their life (and, for as many as a quarter of those chronically infected, result in their death from cirrhosis or liver cancer).
—Tom Bartlett, The Atlantic, 5 Dec. 2025
See All Example Sentences for infect
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Alice Park, Time, 6 Dec. 2025
About half of children with the disease were infected during birth, Children’s Hospital of Philadelphia said, while others caught it from family members.
—Cara Lynn Shultz, PEOPLE, 6 Dec. 2025
Infants and children who are infected with hepatitis B are more likely to develop chronic disease, including about 90% of infants and 30% of children ages 1 to 5.
—Brenda Goodman, CNN Money, 6 Dec. 2025
The rationale for giving the vaccine right away is to wipe out an infection that will afflict the majority of people who contract it as babies for the rest of their life (and, for as many as a quarter of those chronically infected, result in their death from cirrhosis or liver cancer).
—Tom Bartlett, The Atlantic, 5 Dec. 2025
See All Example Sentences for infect
Cite this Entry
“Infect.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/infect. Accessed 8 Dec. 2025.
Copy CitationKids Definition
infect
verb
in·fect
in-ˈfekt 
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
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