Student left with something quite profitable (7)
I believe the answer is:
learner
'student' is the definition.
(thesaurus)
'left with something quite profitable' is the wordplay.
'left' becomes 'l' (common abbreviation).
'with' says to put letters next to each other.
'something quite profitable' becomes 'earner'.
'l'+'earner'='LEARNER'
(Other definitions for learner that I've seen before include "One with an L-plate" , "Unqualified driver" , "Someone undergoing education" , "Disciple" , "One ascertaining" .)