diamondback reptile (8)
I believe the answer is:
terrapin
'diamondback reptile' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for terrapin that I've seen before include "Swimmer" , "A reptile; a printer (anag.)" , "Give out" , "edible, freshwater reptile" , "Small freshwater turtle" .)