Quaker's joint alliance (10)
I believe the answer is:
friendship
'alliance' is the definition.
(thesaurus)
'quaker's joint' is the wordplay.
'quaker's' becomes 'friends' ('Friend' can be a synonym of 'quaker').
'joint' becomes 'hip' (hip is a kind of joint).
'friends'+'hip'='FRIENDSHIP'
(Other definitions for friendship that I've seen before include "Relation between mates" , "Amity" , "camaraderie" .)