Dire March time (4)
I believe the answer is:
ides
'dire march time' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ides that I've seen before include "'''Beware the ... of March'' (Julius Caesar) (4)'" , "Day in Roman months" , "15 March, say -- key date for Caesar" , "Caesar's fateful day" , "Julius Caesar was killed during the . . . . of March" .)