An expert at backing horses (7)
I believe the answer is:
saddler
'an expert' is the definition.
The answer and definition can be both people as well as being singular nouns.
Perhaps they are linked in a way I don't understand?
I cannot understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for saddler that I've seen before include "Leather-worker" , "One makes leather goods for horses" , "I'll make seat" , "Maker of horse's equipment" , "Maker of seats for riders" .)