Famous Roman feline circle (4)
I believe the answer is:
cato
'famous roman' is the definition.
(I've seen this in another clue)
'feline circle' is the wordplay.
'feline' becomes 'cat' (cat is a kind of feline).
'circle' becomes 'O' (O is a circle).
'cat'+'o'='CATO'
(Other definitions for cato that I've seen before include "Marcus Porcius - , Roman politician, censor" , "Senator" , "Roman statesman" , "Ancient Roman censor" , "classical writer" .)