Suspect a trap after I'm on Ecstasy (7)
I believe the answer is:
imagine
'suspect' is the definition.
(thesaurus)
'a trap after i'm on ecstasy' is the wordplay.
'trap' becomes 'gin' (I've seen this before**).
'after' says to put letters next to each other.
'on' is a charade indicator (letters next to each other).
'ecstasy' becomes 'e' (informal term for the drug).
'a' put next to 'gin' is 'agin'.
'agin' put after 'im' is 'imagin'.
'imagin'+'e'='IMAGINE'
(Other definitions for imagine that I've seen before include "Fancy - Lennon song" , "Believe to be so, suppose" , "See something that doesn't exist" , "Assume" , "Reckon" .)