Rowdy gents are cut off (8)
I believe the answer is:
estrange
'cut off' is the definition.
(I've seen this before)
'rowdy gents are' is the wordplay.
'rowdy' indicates an anagram.
'gents'+'are'='gentsare'
'gentsare' is an anagram of 'ESTRANGE'.
(Other definitions for estrange that I've seen before include "Arouse hostility" , "Divorce" , "Get cut off" , "Make enemy of sergeant" , "may break up" .)