Swamp critter, for short
I believe the answer is:
croc
'swamp critter for short' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for croc that I've seen before include "creature heard to be a vicious one" , "Pot tailless" , "Wild animal" , "Large predatory reptile (colloq.)" , "Short reptile" .)