Royal messenger (6)
I believe the answer is:
herald
'royal messenger' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for herald that I've seen before include "and 14: 'Hark! The -- -- sing' (carol)" , "Person who announces important news" , "Official crier or messenger" , "Proclaim the approach of, like old messenger" , "Harbinger, messenger" .)