Unique cat’s back to eat end of lemon peel (9)
I believe the answer is:
nonpareil
'unique' is the definition.
(I've seen this before)
'back to eat end of lemon peel' is the wordplay.
'back to' becomes 'noil' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'eat' is an insertion indicator.
'end of' says to take the final letters.
'peel' becomes 'pare' (synonyms).
The final letter of 'lemon' is 'n'.
'n'+'pare'='npare'
'noil' placed around 'npare' is 'NONPAREIL'.
'cat's' acts as a link.
This may not be correct. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for nonpareil that I've seen before include "like none other" , "Unique type" , "Super model" , "Peerless" , "having no match" .)