Brave man to vex six-footer (7)
I believe the answer is:
gallant
'brave man' is the definition.
'vex six-footer' is the wordplay.
'vex' becomes 'gall' (both can mean to irritate).
'six footer' becomes 'ant' (an ant has six feet).
'gall'+'ant'='GALLANT'
'to' is the link.
(Other definitions for gallant that I've seen before include "lover" , "Noble, chivalrous" , "Brave; courteous" , "Chivalrous - dashing" , "Brave and honourable" .)