Clubs and diamonds: bridge often going over these (7)
I believe the answer is:
drivers
'clubs' is the definition.
(driver is a kind of club)
I can't explain the remainder of the clue.
Can you help me to learn more?
(Other definitions for drivers that I've seen before include "Motoring" , "Chauffeurs" , "Golf clubs" , "9 [CLUBS]" , "Motorists; clubs" .)