Match about to stop season (5)
I believe the answer is:
agree
'match' is the definition.
(as in two tallies agreeing or matching)
'about to stop season' is the wordplay.
'about' becomes 're' (regarding).
'to stop' is an insertion indicator (stopping can mean blocking a gap).
'season' becomes 'age' (season can mean a period or age).
're' placed within 'age' is 'AGREE'.
(Other definitions for agree that I've seen before include "Eager (anag)" , "Be of one mind" , "Allow" , "concede" , "chime?" .)