Support Remain (4)
I believe the answer is:
This clue is a double definition.
'support' is the first definition.
(stay is a kind of support)
'remain' is the second definition.
(I know that remain can be written as stay)
(Other definitions for stay that I've seen before include "Remain; suspend" , "Supporting rope; remain" , "Supporting rope or wire" , "Corset strut" , "Rope or wire used to support a mast" .)