Genuine sort of earl (4)
I believe the answer is:
real
'genuine' is the definition.
(I know that genuine can be written as real)
'sort of earl' is the wordplay.
'sort of' indicates anagramming the letters.
'earl' with letters rearranged gives 'REAL'.
(Other definitions for real that I've seen before include "---- Madrid, Spanish football club" , "Madrid FC; genuine" , "Actual, existing" , "'Genuine, actual (4)'" , "Working together" .)