dawdle
dawdler
drone
foot-dragger
goldbrick
goof-off
laggard
lie-abed
lingerer
loiterer
plodder
procrastinator
sleepyhead
slow goer
slow-foot
slowbelly
slowcoach
slug
sluggard
snail
stick-in-the-mud
straggler
tortoise
lagger
poke
trailer