Fitting end to reform having rejected supporter (4)
I believe the answer is:
meet
'fitting' is the definition.
('meet' can be a synonym of 'fitting')
'end to reform having rejected supporter' is the wordplay.
'end to' suggests the final letters.
'having' is a charade indicator (letters next to each other).
'rejected' is a reversal indicator.
'supporter' becomes 'tee' (I've seen this in other clues**).
The last letter of 'reform' is 'm'.
'tee' written backwards gives 'eet'.
'm'+'eet'='MEET'
(Other definitions for meet that I've seen before include "sporting occasion" , "counter" , "Fitting - encounter" , "Hunting gathering" , "Converge" .)