From Middle English infesten, from Old French infester (to infest), from Latin īnfestō (assail, molest, verb), from īnfestus (hostile).


  • IPA(key): /ɪnˈfɛst/
  • (file)
  • Rhymes: -ɛst


Aphids infest a rosebush

infest (third-person singular simple present infests, present participle infesting, simple past and past participle infested)

  1. (transitive) To inhabit a place in unpleasantly large numbers; to plague, harass.
    Insects are infesting my basement!
    • c. 1611, William Shakespeare, The Tempest, Act V, Scene 1,[1]
      Sir, my liege,
      Do not infest your mind with beating on
      The strangeness of this business; at pick’d leisure
      Which shall be shortly, I’ll resolve you,
      Which to you shall seem probable, of every
      These happen’d accidents; till when, be cheerful
      And think of each thing well.
    • 1724, Daniel Defoe, A General History of the Pirates, London: T. Warner, 2nd edition, Introduction, p. 24,[2]
      I come now to speak of the Pyrates infesting the West-Indies, where they are more numerous than in any other Parts of the World, on several Reasons []
    • 1774, Oliver Goldsmith, An History of the Earth, and Animated Nature, London: J. Nourse, Volume 2, Chapter 12, p. 275,[3]
      It has often happened, that whole caravans have perished in crossing those deserts, either by the burning winds that infest them, or by the sands which are raised by the tempest, and overwhelm every creature in certain ruin.
    • 1847, Herman Melville, Omoo, Chapter 3,[4]
      Nor was the biscuit much better; nearly all of it was broken into hard, little gunflints, honeycombed through and through, as if the worms usually infesting this article in long tropical voyages had, in boring after nutriment, come out at the antipodes without finding anything.
  2. (pathology, of a parasite) To invade a host plant or animal.


Related termsEdit



infest (comparative more infest, superlative most infest)

  1. (obsolete) Mischievous; hurtful; harassing.
    • 1567, Arthur Golding (translator), Metamorphosis by Ovid, Book Four, cited in Thomas Warton, The History of English Poetry, Volume 3, London: J. Dodsley et al., 1781, Section 40, p. 412,[5]
      [] The swarme of scaled snakes
      Did make an yrksome noyce to heare, as she her tresses shakes.
      About her shoulders some did craule, some trayling downe her brest,
      Did hisse, and spit out poison greene, and spirt with tongues infest.
    • 1596, Edmund Spenser, The Faerie Queene, Book VI, Canto Four, Stanza 5, Hackett, 2006, p. 55,
      He stayed not t’advize, which way were best
      His foe t’assayle, or how himselfe to gard,
      But with fierce fury and with force infest
      Upon him ran []


infest (uncountable)

  1. (obsolete) Hostility.
    • 1590, Edmund Spenser, The Faerie Queene, Book II, Canto Eleven, Stanza 32, Hackett, 2006, p. 191,
      Like as a fire, the which in hollow cave
      Hath long bene underkept, and down supprest,
      With murmurous disdayne doth inly rave,
      And grudge, in so streight prison to be prest,
      At last breakes forth with furious infest,
      And strives to mount unto his native seat []