Promoter of mixed doubles? (10)
I believe the answer is:
matchmaker
'promoter of mixed doubles?' is the definition.
The answer and definition can be both people as well as being singular nouns.
Maybe you can see an association between them that I don't see?
This is all the clue.
Can you help me to learn more?
(Other definitions for matchmaker that I've seen before include "worker responsible for strikers leaving the factory?" , "Cupid" , "Union organiser" , "One seeking to bring couples together" , "One who arranges marriages for others" .)