Definition of louse in English:

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Pronunciation: /lous/


1 (plural lice /līs/) A small, wingless, parasitic insect that lives on the skin of mammals and birds.
  • (sucking louse) An insect with piercing mouthparts, found only on mammals (order Anoplura or Siphunculata). See also body louse, head louse (biting louse) An insect with a large head and jaws, found chiefly on birds (order Mallophaga)..
Example sentences
  • Head lice are insects living on the human scalp and feeding on blood.
  • Head lice are insects that live on the scalp and neck.
  • Presumably mineral oil is acting like petroleum jelly to smother the live lice and loosen nits.
1.1Used in names of small invertebrates that parasitize aquatic animals or infest plants, e.g., fish louse.
Example sentences
  • Sea spiders and sea lice have a cavity of body fluid as salty as the sea itself.
  • They are also hosts to a number of blood parasites and feather lice.
  • Sea trout numbers collapsed in 1989 with many sea trout caught in the net heavily infested with sea lice.
2 (plural louses) informal A contemptible or unpleasant person.
Example sentences
  • Since his original plan of using leftover roach motels now seems impractical, Jack must devise a better means of sending these unlicensed louses back to where they belong.
  • His characters were cads, letches, and leering louses, but they effectively tapped a bit of that inappropriate urge in us all.
  • All of these characters - if we can indeed call them that - are despicable louses that lie, cheat, and backstab each other in the name of comedy and TV ratings.


[with object]
1 (louse something up) informal Spoil or ruin something: he loused up my promotion chances
More example sentences
  • Your summer has been a colossal mess, but other folks have been lousing things up, too.
  • Rebecca has an unerring ear for the ways mismatched people relate, an open heart for the ways they louse things up.
  • They then took this cleaner to their design team who loused it up for probably for more money!
2 archaic Remove lice from.
Example sentences
  • They were lousing each other; and it surprised us that they did not discontinue their work + as we entered.
  • When the girl and the lion first appear in the tale we are told that she is lousing him, which illustrates the bond between them.
  • The grandmother began lousing him again and soon he was asleep and snoring loud enough to rattle the windows.


Old English lūs, (plural) lȳs, of Germanic origin; related to Dutch luis, German Laus.

Words that rhyme with louse

douse, dowse, Gauss, grouse, house, Klaus, Manaus, mouse, nous, Rouse, souse, spouse, Strauss

For editors and proofreaders

Syllabification: louse

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