Is in set with six playing (6)
I believe the answer is:
exists
'is' is the definition.
The answer and definition can be both to do with fundamental existence as well as being verbs in their -s form.
Perhaps you can see an association between them that I can't see?
'set with six playing' is the wordplay.
'with' is a charade indicator (letters next to each other).
'playing' indicates an anagram.
'set'+'six'='setsix'
'setsix' with letters rearranged gives 'EXISTS'.
'in' is the link.
Can you help me to learn more?
(Other definitions for exists that I've seen before include "Has life" , "Has objective reality" , "Is extant" , "Lives" , "Subsists" .)