Well preserved Plotinus works (8)
I believe the answer is:
unspoilt
'well preserved' is the definition.
'unspoilt' can be an answer for 'preserved' (I've seen this before). I am unsure of the 'well' bit.
'plotinus works' is the wordplay.
'works' indicates anagramming the letters (letters worked into a new form).
'plotinus' with letters rearranged gives 'UNSPOILT'.
Can you help me to learn more?
(Other definitions for unspoilt that I've seen before include "Retaining its original character" , "Natural - perfect" , "Not impaired or ruined" , "without nasty development?" , "Not marred by development" .)