infest

verb

in·​fest in-ˈfest 

infested; infesting; infests

transitive verb

1

: to spread or swarm in or over in a troublesome manner

a slum infested with crime

shark-infested waters

2

: to live in or on as a parasite

infestant

in-ˈfe-stənt 

noun

infestation

ˌin-ˌfe-ˈstā-shən 

noun

infester

in-ˈfe-stər 

noun

Synonyms

• overrun

Examples of infest in a Sentence

in desperation, we called in an exterminator because the house was infested with ants

Recent Examples on the Web

Radishes are another cabbage relative that can be infested by problematic pests like aphids and flea beetles. —Brandee Gruener, Southern Living, 15 June 2025

Ants will swarm plants that are infested with spider mites, cabbage loopers, root maggots, beetle grubs, scale, mealybugs, ticks, or other pests that ants feed on. —Lauren Landers, Better Homes & Gardens, 21 May 2025

Dance clips infested Nico Nico Douga and fans outlined the steps so everyone could bop along. —Kieran Press-Reynolds, Pitchfork, 14 May 2025

Plants infested with mealybugs usually become weakened and display wrinkled, shriveled leaves. —Sheryl Geerts, Better Homes & Gardens, 21 May 2025

Word History

Etymology

French infester, from Latin infestare, from infestus hostile

First Known Use

1602, in the meaning defined at sense 1

Rhymes for infest

• abreast
• accessed
• addressed
• appressed
• armrest
• arrest
• assessed
• attest
• backrest
• behest
• bequest
• caressed

Kids Definition

infest

verb

in·​fest in-ˈfest 

1

: to spread or swarm in or over in a troublesome manner

a neighborhood infested with crime

shark-infested waters

2

: to live in or on as a parasite

horses infested with worms

infestation

ˌin-ˌfes-ˈtā-shən 

noun

Medical Definition

infest

transitive verb

in·​fest in-ˈfest 

: to live in or on as a parasite

the flea that infests cats

horses infested with worms

compare infect