Gator's cousin (4)
I believe the answer is:
croc
'gator's cousin' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for croc that I've seen before include "Fierce beast" , "Dangerous reptile" , "Predatory reptile (abbr)" , "Small animal" , "Single-handed mariner's nemesis" .)