The Collaborative International Dictionary of English v.0.48:

Mope \Mope\, v. i. [imp. & p. p. Moped; p. pr. & vb. n.
   Moping.] [Cf. D. moppen to pout, Prov. G. muffen to sulk.]
   To be dull and spiritless; to spend time doing little; as, to
   mope around the house. "Moping melancholy." --Milton.
   [1913 Webster]

         A sickly part of one true sense
         Could not so mope.                       --Shak.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

29 Moby Thesaurus words for "moping":
   beetle-browed, black, black-browed, brooding, broody, chapfallen,
   crestfallen, dark, dejected, dour, dumpish, frowning, glowering,
   glum, grim, grum, long-faced, lowering, melancholy, moodish, moody,
   mopey, mopish, morose, mumpish, scowling, sulky, sullen, surly