Scout risked regularly to swear (5)
I believe the answer is:
curse
'swear' is the definition.
('curse' can be a synonym of 'swear')
'scout risked regularly' is the wordplay.
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
'scout'+'risked'='scoutrisked'
The alternate letters of 'scoutrisked' are 'CURSE'.
'to' acts as a link.
(Other definitions for curse that I've seen before include "Invoke evil upon" , "use bad language" , "Oath or a call for evil to come upon person" , "Wish evil upon" , "Trouble" .)