A just claim wouldn't you say? (5)
I believe the answer is:
right
'a just claim' is the definition.
(as in a legal right in the justice system)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for right that I've seen before include "Privy Councillors are so honourable" , "licence" , "Correct; proper" , "Authority - one hand" , "ideal" .)