WWII general Bradley (4)
I believe the answer is:
'wwii general bradley' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for omar that I've seen before include "Arab" , "- Khayyam, Persian poet, astronomer and mathematician" , "and 16 Down: Persian poet" , "- Khayyam, Pers. poet" , "- Sharif, film actor" .)