Cat and reptile - explosive (13)
I believe the answer is:
tortoiseshell
'cat' is the definition.
(tortoiseshell is a kind of cat)
'reptile explosive' is the wordplay.
I cannot quite understand how this works, but
'reptile' could be 'tortoise' (tortoise is a kind of reptile) and 'tortoise' is present in the answer.
'explosive' could be 'he' (abbreviation for high explosive) and 'he' is found in the answer.
This explanation may well be incorrect...
'and' is the link.
Can you help me to learn more?
(Other definitions for tortoiseshell that I've seen before include "Ornamental material" , "The case of the slow-moving" , "Butterfly - yellow-brown mottled material" , "Mottled plated ornamental substance" , "Domestic cat mottled in brownish-yellow and black" .)