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' is a charade indicator (letters next to each other).
'gutted' says to hollow out the word (remove centre letters) (to gut something is to remove its insides).
'hideous' with its centre taken out is 'hs'.
'tom' backwards is '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" .)