Blue blooded boys (5)
I believe the answer is:
royal
'blue' is the definition.
(royal blue is a kind of blue)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for royal that I've seen before include "Member of ruling family" , "complete" , "Queen, say?" , "- - Shakespeare Company (RSC)" , "King, queen, prince or princess?" .)