Stake; mail (4)
I believe the answer is:
post
This clue is a double definition.
'stake' is the first definition.
(I know that stake can be written as post)
'mail' is the second definition.
(I know that mail can be written as post)
(Other definitions for post that I've seen before include "Pole - position" , "may be winning" , "Mail; wooden stake" , "picket" , "a placement: it's > part of one's goal" .)