Remain a supporter (4)
I believe the answer is:
stay
I believe this is a double definition.
'remain' is the first definition.
(staying is a kind of remaining)
'a supporter' is the second definition.
(thesaurus)
(Other definitions for stay that I've seen before include "Corset strut" , "Supporting rope; remain" , "Supporter" , "Don't go!" , "Reside" .)