Choosing body, mischievous spirit with reader on ecstasy (10)
I believe the answer is:
electorate
'choosing body' is the definition.
(body of people choosing or electing someone)
'mischievous spirit with reader on ecstasy' is the wordplay.
'mischievous spirit' becomes 'ate' (I can't justify this - if you can you should believe this answer much more).
'with' is a charade indicator (letters next to each other).
'reader' becomes 'lector' (synonyms).
'on' is a charade indicator (letters next to each other).
'ecstasy' becomes 'E' (informal term for the drug).
'lector' put after 'e' is 'elector'.
'ate' after 'elector' is 'ELECTORATE'.
Can you help me to learn more?
(Other definitions for electorate that I've seen before include "Everyone choosing" , "Voters as a whole" , "choosing body" , "Those qualified to vote" , "Those entitled to vote" .)