Source : Webster's Revised Unabridged Dictionary (1913)

Wasteful \Waste"ful\, a.
   1. Full of waste; destructive to property; ruinous; as,
      wasteful practices or negligence; wasteful expenses.

   2. Expending, or tending to expend, property, or that which
      is valuable, in a needless or useless manner; lavish;
      prodigal; as, a wasteful person; a wasteful disposition.

   3. Waste; desolate; unoccupied; untilled. [Obs.]

            In wilderness and wasteful desert strayed.
                                                  --Spenser.

   Syn: Lavish; profuse; prodigal; extravagant. --
        {Waste"ful*ly}, adv. -- {Waste"ful*ness}, n.

Source : WordNet®

wastefully
     adv : to a wasteful manner or to a wasteful degree; "we are still
           prodigally rich compared to others" [syn: {prodigally}]