Summer for one academic mostly trouble (5)
I believe the answer is:
donna
'summer' is the definition.
(musician Donna Summer)
'one academic mostly trouble' is the wordplay.
I cannot really understand how this works, but
'one' could be 'a' (a thing is one thing) and 'a' is located in the answer.
'academic' could be 'don' (type of academic - especially at Oxbridge) and 'don' is found in the answer.
A single letter 'n' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
'for' is the link.
Can you help me to learn more?
(Other definitions for donna that I've seen before include "See 10" , "Italian woman of rank" , "Spanish lady's title" , "Female" , "Title of Spanish or Portuguese lady" .)