Source : Webster's Revised Unabridged Dictionary (1913)

Procrastinator \Pro*cras"ti*na`tor\, n.
   One who procrastinates, or defers the performance of
   anything.

Source : WordNet®

procrastinator
     n : someone who postpones work (especially out of laziness or
         habitual carelessness) [syn: {postponer}, {cunctator}]