Just terrible losing crown (8)
I believe the answer is:
rightful
'just' is the definition.
(similar in meaning)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for rightful that I've seen before include "Proper - legitimate" , "Legitimate, fitting" , "Legitimately claimed" , "Lawful" , "According to justice" .)