Inmate rips off single Republican (8)
I believe the answer is:
prisoner
'inmate' is the definition.
(I've seen this before)
'rips off single republican' is the wordplay.
'off' indicates an anagram.
'single' becomes 'one' (a single thing - only one).
'republican' becomes 'R' (abbreviation in US politics).
'rips' anagrammed gives 'pris'.
'pris'+'one'+'r'='PRISONER'
(Other definitions for prisoner that I've seen before include "One locked up" , "One kept confined" , "Captive or criminal in jail" , "Captive, detainee" , "Inmate doing porridge" .)