Cat turns up with hideous gutted insects (5)
I believe the answer is:
moths
'insects' is the definition.
(moth is a kind of insect)
'cat turns up with hideous gutted' is the wordplay.
'cat' becomes 'tom' (a tom is a male cat).
'turns up' is a reversal indicator.
'with' means one lot of letters go next to another.
'gutted' means to remove the middle letters (to gut something is to remove its insides).
'hideous' with its middle removed is 'hs'.
'tom' reversed gives 'mot'.
'mot'+'hs'='MOTHS'
(Other definitions for moths that I've seen before include "Nocturnal insects that breed in cloth" , "Night-flying insects" , "They're attracted to light" , "Insects related to butterflies" .)