Frank in golf tournament (4)
I believe the answer is:
open
I believe this clue is a double definition.
'frank' is the first definition.
(synonyms)
'golf tournament' is the second definition.
(the Open is a golf tournament)
'in' is the link.
(Other definitions for open that I've seen before include "Frank, candid" , "Release" , "Public" , "Not enclosed" , "Frank; unfold" .)