A slowcoach (8)
I believe the answer is:
tortoise
'a slowcoach' is the definition.
(tortoises are slow animals)
This is the entire clue.
(Other definitions for tortoise that I've seen before include "Slow reptile that raced a hare" , "Land turtle" , "Shelled reptile" , "Turtle-like reptile" , "Tie roots (anag)" .)