Various loons on ecstasy (7)
I believe the answer is:
diverse
'various' is the definition.
('diverse' can be a synonym of 'various')
'loons on ecstasy' is the wordplay.
'loons' becomes 'divers' ('diver' can be a synonym of 'loon').
'on' says to put letters next to each other.
'ecstasy' becomes 'e' (informal term for the drug).
'divers'+'e'='DIVERSE'
(Other definitions for diverse that I've seen before include "Differing" , "'Various, assorted (7)'" , "Of different kind or variety" , "Book" , "Different and various" .)