Horse breed (4)
I believe the answer is:
arab
'horse breed' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for arab that I've seen before include "Horse of a breed originating in the Middle East" , "Saudi or Omani, perhaps" , "Saudi, e.g." , "Saudi, perhaps - breed of horse" , "Qatari or Omani, say" .)