infect

verb

in·​fect in-ˈfekt 

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

in-ˈfek-tər 

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

People usually get infected with the bacteria by eating raw shellfish, especially oysters, or through an open wound that has direct contact with saltwater. —Michelle Marchante, Miami Herald, 29 Apr. 2025

The people getting infected have not received the vaccine or are behind on their doses. —Joseph States, Chicago Tribune, 28 Apr. 2025

Many people are actually infected with H. pylori and don’t experience any symptoms, but around 15% will go on to develop an ulcer in either their stomach (known as a gastric ulcer) or a portion of the small intestine called the duodenum (known as a duodenal ulcer). —Caroline Tien, SELF, 28 Apr. 2025

Lower levels of immunity have already resulted in a recent outbreak in western Texas that has killed two children, infected more than 620 people, and hospitalized 64 others. —Laura Baisas, Popular Science, 24 Apr. 2025

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

Phrases Containing infect

• co-infect

Rhymes for infect

• affect
• aspect
• bedecked
• bisect
• collect
• connect
• correct
• deflect
• detect
• direct
• dissect
• effect

Kids 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

infector

-ˈfek-tər 

noun

Medical Definition

infect

transitive verb

in·​fect in-ˈfekt 

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