\ ˈlau̇s How to pronounce louse (audio) \

Definition of louse

 (Entry 1 of 2)

1 plural lice\ ˈlīs How to pronounce lice (audio) \

a : any of various small wingless usually flattened insects (orders Anoplura and Mallophaga) parasitic (see parasite sense 2) on warm-blooded animals
b : a small usually sluggish arthropod (such as a biting louse) that lives on other animals or on plants and sucks their blood or juices
c : any of several small arthropods (such as a book louse) that are not parasitic
2 plural louses\ ˈlau̇-​səz How to pronounce louses (audio)\ : a contemptible person : heel what a beast, what a cad, what a louse he had been— Walter Karig


\ ˈlau̇s How to pronounce louse (audio) , ˈlau̇z How to pronounce louse (audio) \
loused; lousing

Definition of louse (Entry 2 of 2)

transitive verb

: to remove lice from

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Synonyms for louse

Synonyms: Noun

bastard, beast, bleeder [British], blighter [chiefly British], boor, bounder, bugger, buzzard, cad, chuff, churl, clown, creep, cretin, crud [slang], crumb [slang], cur, dirtbag [slang], dog, fink, heel, hound, jerk, joker, lout, pill, rat, rat fink, reptile, rotter, schmuck [slang], scum, scumbag [slang], scuzzball [slang], skunk, sleaze, sleazebag [slang], sleazeball [slang], slime, slimeball [slang], slob, snake, so-and-so, sod [chiefly British], stinkard, stinker, swine, toad, varmint, vermin

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Examples of louse in a Sentence


a problem with head lice Her ex-husband is a real louse.

Recent Examples on the Web: Noun

Consider the speckled sea louse (Eurydice pulchra). Douglas Main, National Geographic, "Why oysters close on the full moon—and more odd lunar effects on animals," 17 Apr. 2019 Thanks to evolution, the pesky parasites known as lice have become resistant to most over-the-counter treatments. Good Housekeeping, "Yikes! Super-Strains of Lice Have Spread to 25 States," 26 Feb. 2016 Granted, a reference to louse is not unique to Bethel, about 400 miles (640 kilometers) west of Anchorage. Rachel D'oro, The Seattle Times, "Alaska town seeks to remove ‘Lousetown’ nickname from code," 10 Sep. 2018 The word louse refers to unpleasant or contemptible people. Rachel D'oro, The Seattle Times, "Alaska town seeks to remove ‘Lousetown’ nickname from code," 10 Sep. 2018 Since lice are big fans of the hair surrounding the genitals, using condoms won’t protect you, the CDC explains. Korin Miller, SELF, "These Are the Only Kinds of Birth Control That Also Protect Against STIs," 27 July 2018 Each female louse can produce two strings of 1,000 eggs, which means infestations spread quickly within concentrated populations of captive fish. Amanda Little, WIRED, "The Laser Battle Against Blood-Sucking Parasites of the Deep," 23 May 2018 As liquid builds up inside the louse, its internal organs start to shut down from the exhaustion of trying to pump out the water. Karen Weintraub, Scientific American, "Revenge of the Super Lice," 1 June 2017 The ex-husband is uncaring, amoral, self-assured, breezy, confident and a total louse, a convincing case of opposites attracting. Mick Lasalle, Houston Chronicle, "Review: ‘Boundaries’ a trip to nowhere," 3 July 2018

Recent Examples on the Web: Verb

Will Ferrell figure out a way to get along, their fathers (Mel Gibson, John Lithgow) show up for the holidays to louse everything up in this comedy sequel. Chris Foran, Milwaukee Journal Sentinel, "Milwaukee fall movie guide: 48 movies, 4 festivals, 11 weeks," 31 Aug. 2017

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'louse.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of louse


before the 12th century, in the meaning defined at sense 1a


14th century, in the meaning defined above

History and Etymology for louse

Noun and Verb

Middle English lous, from Old English lūs; akin to Old High German lūs louse, Welsh llau lice

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Dictionary Entries near louse






louse up


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Time Traveler for louse

The first known use of louse was before the 12th century

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English Language Learners Definition of louse

: a type of small insect that lives on the bodies of people or animals
informal : a bad or cruel person


\ ˈlau̇s How to pronounce louse (audio) \
plural lice\ ˈlīs \

Kids Definition of louse

1 : a small, wingless, and usually flat insect that lives on the bodies of warm-blooded animals
2 : an insect or related arthropod that resembles a body louse and feeds on plant juices or decaying matter


\ ˈlau̇s How to pronounce louse (audio) \
plural lice\ ˈlīs How to pronounce lice (audio) \

Medical Definition of louse

: any of the small wingless usually flattened insects that are parasitic on warm-blooded animals and constitute the orders Anoplura and Mallophaga

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More from Merriam-Webster on louse

Rhyming Dictionary: Words that rhyme with louse

Thesaurus: All synonyms and antonyms for louse

Spanish Central: Translation of louse

Nglish: Translation of louse for Spanish Speakers

Britannica English: Translation of louse for Arabic Speakers

Britannica.com: Encyclopedia article about louse

Comments on louse

What made you want to look up louse? Please tell us where you read or heard it (including the quote, if possible).


one from the Upper Peninsula of Michigan

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