What is the X in X-mas?
late 14c., late 13c. as a surname, "habitually lazy person," from Middle English sluggi "sluggish, indolent," probably from a Scandinavian word; cf. 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.
'Tis the voice of a sluggard -- I heard him complain:As an adjective meaning "sluggish, lazy" from 1590s. Related: Sluggardly.
"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]