Pole split bill with US gladiator (9)
I believe the answer is:
spartacus
'gladiator' is the definition.
(I've seen this before)
'pole split bill with us' is the wordplay.
'pole' becomes 's' (abbreviation for South, as in South Pole).
'split' becomes 'part' (synonyms).
'bill' becomes 'ac' (short for account).
'with' is a charade indicator (letters next to each other).
's'+'part'+'ac'+'us'='SPARTACUS'
(Other definitions for spartacus that I've seen before include "Leader of the slave revolt against Rome, 73BC" , "Roman slave who led an uprising against Roman legions" , "Rebellious Roman slave. d. c.71BC" , "Rebel Roman slave" , "Old fighter" .)