Source : Webster's Revised Unabridged Dictionary (1913)

Slugabed \Slug"a*bed`\, n.
   One who indulges in lying abed; a sluggard. [R.] ``Fie, you
   slugabed!'' --Shak.

Source : WordNet®

slugabed
     n : a person who stays in bed until a relatively late hour [syn:
          {lie-abed}]