WordNet sense 1 (someone who takes more time than necessary; someone who lags behind):

dawdler, drone, poke, trailer, lagger

WordNet sense 2 (inclined to waste time and lag behind):

dilatory

WordNet sense 3 (not punctual; after the appointed time):

unpunctual

WordNet sense 4 (wasting time):

pokey, poky

WordNet sense 5 (not moving quickly; taking a comparatively long time):

slow