slug (n.1)

late 14c., late 13c. as a surname, "habitually lazy person," from Middle English sluggi "sluggish, indolent," probably from a Scandinavian word such as dialectal Norwegian slugga "be sluggish," dialectal Norwegian sluggje "heavy, slow person," dialectal Swedish slogga "to be slow or sluggish." Adjective sluggy is attested in English from early 13c. As an adjective meaning "sluggish, lazy" from 1590s. Related: Sluggardly.

'Tis the voice of a sluggard — I heard him complain:

"You have wak'd me too soon, I must slumber again."

[Isaac Watts, 1674-1748]

***

'Tis the voice of the Lobster: I heard him declare

"You have baked me too brown, I must sugar my hair."

["Lewis Carroll" (Charles L. Dodgson), 1832-1898]

c. 1300, "the killing of a person, murder; the killing of large numbers of persons in battle;" mid-14c., "the killing of a cattle or sheep for food;" from a Scandinavian source akin to Old Norse slatr "a butchering, butcher meat," slatra "to slaughter," slattr "a mowing," related to Old Norse sla "to strike," from Proto-Germanic *slagan- (see slay (v.)).

The form was perhaps influenced by Middle English slaught "killing, manslaughter, carnage; butchery of animals," the native cognate, from Old English sliht, sleht, slieht "stroke, slaughter, murder, death; animals for slaughter;" as in sliehtswyn "pig for killing."