Feeling ecstasy joining movement (7)
I believe the answer is:
emotion
'feeling' is the definition.
(I know that emotion is a type of feeling)
'ecstasy joining movement' is the wordplay.
'ecstasy' becomes 'E' (informal term for the drug).
'joining' is a charade indicator (letters next to each other).
'movement' becomes 'motion' (synonyms).
'e'+'motion'='EMOTION'
(Other definitions for emotion that I've seen before include "Feeling such as joy, sorrow and fear" , "Intense feeling" , "Feeling of joy, love, hate etc" , "Hatred or love, say" , "Feeling like love or hate" .)