Extravagant academic exercise (7)
I believe the answer is:
profuse
'extravagant' is the definition.
(thesaurus)
'academic exercise' is the wordplay.
'academic' becomes 'prof'.
'exercise' becomes 'use' ('use' can be a synonym of 'exercise').
'prof'+'use'='PROFUSE'
(Other definitions for profuse that I've seen before include "Overflowing - excessive" , "Plentiful, abundant" , "Plentiful or extravagant" , "Plentiful, generous" , "Lavish or extravagant, could be gratitude or apology" .)