Day for Caesar to "beware" (4)
I believe the answer is:
ides
'day for caesar to beware' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for ides that I've seen before include "day in Rome" , "Mid-month date in Roman calendar" , "For Romans, a day" , "For example, March 15 in the Roman calendar" , "Side of March when Caesar died" .)