__ Baba (3)
I believe the answer is:
ali
'baba' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ali that I've seen before include "Former boxing champion" , "Mohammad . . ., . . . Hewson" , "Cassius Clay became Muhammad ..." , "Ringmaster" , "US heavyweight boxer" .)