Source : Webster's Revised Unabridged Dictionary (1913)

Dawdler \Daw"dler\, n.
   One who wastes time in trifling employments; an idler; a
   trifler.

Source : WordNet®

dawdler
     n : someone who takes more time than necessary; someone who lags
         behind [syn: {drone}, {laggard}, {lagger}, {trailer}]