Definition of infest in US English:



[with object]usually be infested
  • (of insects or animals) be present (in a place or site) in large numbers, typically so as to cause damage or disease.

    ‘the house is infested with cockroaches’
    as adjective, in combination ‘shark-infested waters’
    • ‘I don't think anyone would like the idea of mice or rats in their garden but people feeding birds risk these pests infesting their homes.’
    • ‘Paint flaked off the walls, pests infested the rooms and loose wires hung in plain view.’
    • ‘Instead they are rat infested and neglected while rich people don't have to pay university fees.’
    • ‘It is crumbling worldwide like a white ant infested edifice along with its credibility.’
    • ‘It is being administered medication and a mosquito net has been placed around it so that flies do not infest the wound.’
    • ‘What's with all the hunters infesting these places lately?’
    • ‘It is essential to be aware of the species infesting your fields and to match the treatment timing to those species.’
    • ‘He paved over our yard, because he didn't want ants infesting the house.’
    • ‘Fleas infest the animal (rats, but other rodents as well), and these fleas move freely over to human hosts.’
    • ‘His McGill ghetto apartment is infested with mice and, try as he might, he can't seem to get rid of them.’
    • ‘Many houses were infested with mice, flies, and other unsavoury creatures.’
    • ‘These bugs may infest your bathroom, and jump out of unexpected corners of the closet, but they adhere to the policy of non-violence.’
    • ‘If lice infest the eyebrows or eyelashes, the eyes may also become inflamed.’
    • ‘She hated bugs and wouldn't be caught dead having to do all that walking in the hot bug infested woods.’
    • ‘You might also state the level of care the apartment needs while you are gone - i.e. you might not want to come back to find it a total mess with pests infesting it because your friend never cleaned.’
    • ‘The species was believed to have been wiped out in 1918 when rats infested their home island.’
    • ‘Our landlord had neglected to provide screens, and I was unable to open the windows, lest flies infest the house.’
    • ‘The hospitals were dirty, smelly, rat infested, and lacked basic requirements.’
    • ‘I had heard the media talking about rats infesting Glasgow.’
    • ‘This pest annually infests citrus in Texas, Mexico, and Central America and threatens California and Florida.’
    overrun, spread through, take over, overspread, swarm over, crawl over, run riot over
    overrun, swarming, teeming, crawling, bristling, alive, ridden, infiltrated, permeated
    View synonyms


Late Middle English (in the sense ‘torment, harass’): from French infester or Latin infestare ‘assail’, from infestus ‘hostile’. The current sense dates from the mid 16th century.