louse

[n. lous; v. lous, louz] /n. laʊs; v. laʊs, laʊz/

noun, plural lice

[lahys] /laɪs/ (Show IPA), for 1–3, louses for 4.

any small, wingless insect of the order Anoplura (sucking louse) parasitic on humans and other mammals and having mouthparts adapted for sucking, as Pediculus humanus (body louse or head louse) and Phthirius pubis (crab louse or pubic louse)

any insect of the order Mallophaga (bird louse, biting louse, or chewing louse) parasitic on birds and mammals, having mouthparts adapted for biting.

plant louse.

Slang. a contemptible person, especially an unethical one.

verb (used with object), loused, lousing.

to delouse.

Verb phrases

louse up, Slang. to spoil; botch:

Miscasting loused up the movie.

Origin

before 900; 1910-15 for def 4; Middle English lous(e), luse, plural lise, lice; Old English lūs, plural lȳs; cognate with Dutch luis, German Laus, Old Norse lūs

British Dictionary definitions for louse up

louse

/laʊs/

noun (pl) lice (laɪs)

any wingless bloodsucking insect of the order Anoplura: includes Pediculus capitis (head louse), Pediculus corporis (body louse), and the crab louse, all of which infest man related adjective pedicular

biting louse, bird louse, any wingless insect of the order Mallophaga, such as the chicken louse: external parasites of birds and mammals with biting mouthparts

any of various similar but unrelated insects, such as the plant louse and book louse

(slang) (pl) louses. an unpleasant or mean person

verb (transitive)

to remove lice from

(foll by up) (slang) to ruin or spoil

Word Origin

Old English lūs; related to Old High German, Old Norse lūs

Word Origin and History for louse up

louse

"parasitic insect infecting human hair and skin," Old English lus, from Proto-Germanic *lus (cf. Old Norse lus, Middle Dutch luus, Dutch luis, Old High German lus, German Laus), from PIE *lus- "louse" (cf. Welsh lleuen "louse"). Slang meaning "obnoxious person" is from 1630s. The plural lice (Old English lys) shows effects of i-mutation. The verb meaning "to clear of lice" is from late 14c.; to louse up "ruin, botch" first attested 1934, from the literal sense (of bedding), from 1931.

louse up in Medicine

louse (lous)
n. pl. lice (līs)
Any of numerous small, flat-bodied, wingless biting or sucking insects of the orders Mallophaga or Anoplura, many of which are external parasites on humans.

Slang definitions & phrases for louse up

louse up

verb phrase

To ruin or spill; botch; bollix up: Boy, you certainly loused that up
To fail; screw up: He'll get promoted next month if he doesn't louse up (1938+)

louse

noun

An obnoxious and despicable person, esp one who is devious and undependable; bastard, crumb: We kicked the dirty louse out when he said that (1633+)

Idioms and Phrases with louse up

louse up

Spoil, ruin, bungle. For example, The bad weather loused up our plans, or Your change of mind really loused me up. This slangy expression originated in World War I, when infestation with lice was the common lot of soldiers in the trenches; its figurative use dates from the 1930s.