One man for Caesar to beware of (4)
I believe the answer is:
ides
'caesar to beware of' is the definition.
I can't judge whether this defines the answer.
'one man' is the wordplay.
'one' becomes 'I' (Roman numeral).
'man' becomes 'des' ().
'i'+'des'='IDES'
'for' is the link.
Can you help me to learn more?
(Other definitions for ides that I've seen before include "Caesar was killed in this side of March" , "Caesar's fateful day" , "15/7?" , "Julius Caesar died in these March days" , "mid-month for the Romans" .)