Moonstruck in a cult after processing (7)
I believe the answer is:
lunatic
'moonstruck' is the definition.
(synonyms)
'in a cult after processing' is the wordplay.
'after processing' indicates anagramming the letters (I've seen this in other clues).
'in'+'a'+'cult'='inacult'
'inacult' is an anagram of 'LUNATIC'.
(Other definitions for lunatic that I've seen before include "Type of fringe" , "Harebrained" , "bonkers" , "bananas" , "Bats" .)