Many a wicked spirit? (5)
I believe the answer is:
devil
'spirit?' is the definition.
(I know that devil is a type of evil spirit)
'many a wicked' is the wordplay.
'many' becomes 'd'.
'a wicked' becomes 'evil' (I've seen this in another clue).
'd'+'evil'='DEVIL'
(Other definitions for devil that I've seen before include "Powerful evil spirit" , "Beast" , "Archfiend" , "Wicked person" , "Terror" .)