Caesar's garb (4)
I believe the answer is:
'caesar's garb' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for toga that I've seen before include "This ancient robe might get your goat" , "Got a robe for an old Roman" , "Garment worn by men in ancient Rome" , "Outer garment" , "Roman clothing" .)