Cavalrymen sort rope out (8)
I believe the answer is:
troopers
'cavalrymen' is the definition.
(I've seen this in another clue)
'sort rope out' is the wordplay.
'out' is an anagram indicator (out can mean wrong or inaccurate).
'sort'+'rope'='sortrope'
'sortrope' is an anagram of 'TROOPERS'.
(Other definitions for troopers that I've seen before include "Swearing 19 Downs [SOLDIERS]" , "Cavalrymen" .)