Subject, for example, in fiction (5)
I believe the answer is:
liege
'subject' is the definition.
(I've seen this in another clue)
'example in fiction' is the wordplay.
'example' becomes 'eg' (short for 'exempli gratia', 'for example' in Latin).
'in' indicates putting letters inside.
'fiction' becomes 'lie' (fiction can mean a lie or fabrication).
'eg' put within 'lie' is 'LIEGE'.
'for' is the link.
(Other definitions for liege that I've seen before include "World War one battle site" , "Belgian city on Meuse" , "Belgian city or ancient lord" , "Old sovereign" , "Vassal, subject" .)