Source : Webster's Revised Unabridged Dictionary (1913)

Ponderously \Pon"der*ous*ly\, adv.
   In a ponderous manner.

Source : WordNet®

ponderously
     adv 1: in an uninterestingly ponderous manner; "the play was staged
            with ponderously realistic sets"
     2: in a heavy ponderous manner; "he moves ponderously"