infest

UK: /ɪnˈfɛst/ US: /ɪnˈfɛst/ ,(in fest′)

WordReference Random House Learner's Dictionary of American English © 2025

in•fest /ɪnˈfɛst/   v. [~ + object]

1. to overrun (a place) in a troublesome manner; cause hardship to (a place) by great numbers:
   The mice infested the farmhouse.

in•fes•ta•tion /ˌɪnfɛˈsteɪʃən/  n. 

[countable] infestations of bees in their roof.

[uncountable] the infestation of the roof.

WordReference Random House Unabridged Dictionary of American English © 2025

in•fest  (in fest′), v.t. 

1. to live in or overrun to an unwanted degree or in a troublesome manner, esp. as predatory animals or vermin do:
   Sharks infested the coastline.
2. to be numerous in, as anything undesirable or troublesome:
   the cares that infest the day.
3. [Archaic.] to harass.

• Latin infestāre to assail, molest, derivative of infestus hostile
• late Middle English 1375–1425

in•fest′er, n. 

Collins Concise English Dictionary © HarperCollins Publishers::

infest / ɪnˈfɛst/ verb (transitive)

1. to inhabit or overrun in dangerously or unpleasantly large numbers
2. (of parasites such as lice) to invade and live on or in (a host)

Etymology: 15th Century: from Latin infestāre to molest, from infestus hostile

ˌinfesˈtation noun

inˈfester noun