Cat breed (7)
I believe the answer is:
siamese
'cat breed' is the definition.
(I know that Siamese is a cat breed)
This is the entire clue.
(Other definitions for siamese that I've seen before include "Cat - Thai?" , "Pugnacious aquarium species -- shagginess, if I'm thief (anag)" , "type of cat" , "Thease twins are joined at birth" , "like a cat" .)