also slugabed, 1590s, with bed (n.) + obsolete verb slug "be lazy, intert" (early 15c.), which is perhaps from Scandinavian (see sluggard).
“It is my plea for having been a slug-a-bed this morning,” he answered.
I am no wife for you, a clumsy lout, a slug-a-bed, God forgive me!
Making the sun his alarm clock, he prolonged the slug-a-bed luxury.