Crossword setters and their boss like an old chestnut (4)
I believe the answer is:
used
'an old chestnut' is the definition.
Both the answer and definition are adjectives. Maybe there's a link between them I don't understand?
'crossword setters and their boss' is the wordplay.
I cannot quite understand how this works, but
'setters' could be 'us' (the crossword setter and their colleagues) and 'us' is located in the answer.
'boss' could be 'ed' (short for editor - newspaper boss) and 'ed' is found within the answer.
No letters remain.
This explanation may well be incorrect...
'like' acts as a link.
Can you help me to learn more?
(Other definitions for used that I've seen before include "Brought into play" , "Accustomed - exploited" , "Scottish expert" , "like majority of cars?" , "was milking" .)