He doesnt turn up - a defect in animals (9)
I believe the answer is:
defaulter
'he doesnt turn up a' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'defect in animals' is the wordplay.
'defect' becomes 'fault' (synonyms).
'in' indicates putting letters inside.
'animals' becomes 'deer' (type of animals).
'fault' placed into 'deer' is 'DEFAULTER'.
Can you help me to learn more?
(Other definitions for defaulter that I've seen before include "He fails to show up" , "He hasn't paid his bills" , "Guilty soldier" , "Person avoiding court action" .)