Butcher or sniper as an inmate (8)
I believe the answer is:
prisoner
'an inmate' is the definition.
(I know that inmate can be written as prisoner)
'butcher or sniper' is the wordplay.
'butcher' indicates an anagram.
'or'+'sniper'='orsniper'
'orsniper' anagrammed gives 'PRISONER'.
'as' acts as a link.
(Other definitions for prisoner that I've seen before include "One inside" , "One captured" , "The ---, cult 60s TV series" , "Captive, detainee" , "One kept confined" .)