Check support (4)
I believe the answer is:
stay
I believe this clue is a double definition.
'check' is the first definition.
(staying is a kind of checking)
'support' is the second definition.
(stay is a kind of support)
(Other definitions for stay that I've seen before include "Supporting rod" , "Remain; suspend" , "Remain behind" , "Supporting rope; remain" , "Thin strip used to stiffen a garment" .)