Overwhelming joy (7)
I believe the answer is:
ecstasy
'overwhelming joy' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for ecstasy that I've seen before include "State of rapture" , "Powerful hallucinatory drug" , "Overwhelming joy" , "Bliss, rapture" , "Feeling of immense rapture" .)