Academic in clash or fighting (7)
I believe the answer is:
scholar
'academic' is the definition.
(I've seen this before)
'clash or fighting' is the wordplay.
'fighting' indicates anagramming the letters (I've seen this in other clues).
'clash'+'or'='clashor'
'clashor' anagrammed gives 'SCHOLAR'.
'in' is the link.
(Other definitions for scholar that I've seen before include "Learned type" , "Person of learning" , "Man of letters" , "Student or learned person" , "university type?" .)