The Collaborative International Dictionary of English v.0.48:
Dawdler \Daw"dler\, n. One who wastes time in trifling employments; an idler; a trifler. [1913 Webster]WordNet (r) 3.0 (2006):
dawdler n 1: someone who takes more time than necessary; someone who lags behind [syn: dawdler, drone, laggard, lagger, trailer, poke]