Evil party operated out of the public eye (9)
I believe the answer is:
privately
'out of the public eye' is the definition.
Both the definition and answer are adverbs. Perhaps there's an association between them I don't understand?
'evil party operated' is the wordplay.
'operated' is an anagram indicator.
'evil'+'party'='evilparty'
'evilparty' with letters rearranged gives 'PRIVATELY'.
Can you help me to learn more?
(Other definitions for privately that I've seen before include "Avoiding publicity" , "in camera?" .)