Stake in The Post? (6)
I believe the answer is:
picket
I believe this clue is a double definition.
'stake' is the first definition.
(both can mean a post)
'the post?' is the second definition.
(thesaurus)
'in' acts as a link.
(Other definitions for picket that I've seen before include "Type of wooden fence" , "Protesting striker" , "Strike line; stake" , "attempt to extend strike" , "Group of striking workers outside workplace" .)