Judge old King and Queen's jesters (6)
I believe the answer is:
jokers
'jesters' is the definition.
The answer and definition can be both people as well as being plural nouns.
Maybe you can see an association between them that I can't see?
'judge old king and queen's' is the wordplay.
'judge' becomes 'j' (abbreviation for judge).
'old' becomes 'o' (common abbreviation eg in OE for Old English).
'king and queen's' becomes 'kers' (I've seen this in other clues).
'j'+'o'+'kers'='JOKERS'
Can you help me to learn more?
(Other definitions for jokers that I've seen before include "Cards - pranksters" , "Comedians, comics" .)