Benefactor adopting student struggle (8)
I believe the answer is:
flounder
'struggle' is the definition.
(flounder can mean to struggle)
'benefactor adopting student' is the wordplay.
I cannot really understand how this works, but
'student' could be 'l' (as in L-plates for learner drivers) and 'l' is located in the answer.
The remaining letters 'founder' is a valid word which might be clued in a way I don't understand.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for flounder that I've seen before include "Fish; stagger clumsily" , "Fish -- stumble helplessly" , "Have difficulty" , "Predatory fish" , "Move clumsily like flatfish?" .)