Source : Webster's Revised Unabridged Dictionary (1913)

Plump \Plump\, v. t. [imp. & p. p. {Plumped}; p. pr. & vb. n.
   {Plumping}.]
   1. To make plump; to fill (out) or support; -- often with up.

Source : WordNet®

plumping
     adj : very large; of exceptional size for its kind; "won by a
           plumping majority"