Ecstasy bachelor extracted from plant (8)
I believe the answer is:
euphoria
'ecstasy' is the definition.
(I've seen this before)
'bachelor extracted from plant' is the wordplay.
'bachelor' becomes 'B' (abbreviation e.g. BA=Bachelor of Arts).
'extracted from' is a deletion indicator.
'plant' becomes 'euphorbia'.
'euphorbia' with 'b' taken out is 'EUPHORIA'.
(Other definitions for euphoria that I've seen before include "Over-optimism" , "In high spirits" , "A feeling of wild happiness and well-being" , "Ecstatic feeling" , "State of great elation" .)