I note failure to restrain large pet (8)
I believe the answer is:
indulged
'pet' is the definition.
The answer and definition are different parts of speech. However, adjectives and past participle verbs can sometimes define each other.
'i note failure to restrain large' is the wordplay.
'i note failure' becomes 'indued' (I can't explain this - if you can you should believe this answer much more).
'to restrain' is an insertion indicator.
'large' becomes 'lg' (abbreviation).
'indued' going around 'lg' is 'INDULGED'.
Can you help me to learn more?
(Other definitions for indulged that I've seen before include "Pampered" , "Gratified a wish, allowed to have" , "Satisfied (an interest)" , "Gratified the wishes of" .)