Source : Webster's Revised Unabridged Dictionary (1913)

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. ``Moping melancholy.'' --Milton.

         A sickly part of one true sense Could not so mope.
                                                  --Shak.

Source : WordNet®

moped
     n : a motorbike that can be pedaled or driven by a low-powered
         gasoline engine