louse

1 of 2

noun

ˈlau̇s 

1

plural lice ˈlīs 

a

: any of various small wingless usually flattened insects (orders Anoplura and Mallophaga) parasitic 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  : a contemptible person : heel

what a beast, what a cad, what a louse he had been

—Walter Karig

louse

2 of 2

verb

ˈlau̇s  ˈlau̇z 

loused; lousing

transitive verb

: to remove lice from

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

Examples of louse in a Sentence

Noun

a problem with head lice

Her ex-husband is a real louse.

Recent Examples on the Web

Noun

For reasons that included the phylloxera louse—which decimated grapevines in the mid 1800’s—as well as the labor-intensive needs of this grape, by 1987 only 1.2 acres (0.5 hectares) of Timorasso existed in the world. —Tom Mullen, Forbes.com, 21 Apr. 2025

In the mid 19th century, the phylloxera louse decimated vineyards throughout the world. —Tom Mullen, Forbes.com, 6 Apr. 2025

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, 31 Aug. 2017

Word History

Etymology

Noun and Verb

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

First Known Use

Noun

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

Verb

14th century, in the meaning defined above

Phrases Containing louse

• bird louse
• biting louse
• body louse
• book louse
• crab louse
• head louse
• jumping plant louse
• louse up
• plant louse
• short-nosed cattle louse
• sucking louse
• wood louse

Rhymes for louse

• blouse
• bouse
• douse
• dowse
• grouse
• haus
• mouse
• rouse
• spouse
• youse
• alehouse
• almshouse

Kids Definition

louse

noun

ˈlau̇s

1

plural lice

ˈlīs

a

: any of various small wingless usually flat insects that live as parasites on the bodies of warm-blooded animals

b

: any of several other small arthropods (as a book louse or wood louse) that are not parasites

2

plural louses

ˈlau̇-səz

: a mean person

Medical Definition

louse

noun

ˈlau̇s 

plural lice ˈlīs 

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