Idle cowboy's record in this Wild West show? (5)
I believe the answer is:
rodeo
'wild west show?' is the definition.
(I've seen this before)
I don't understand how the rest of the clue works.
(Other definitions for rodeo that I've seen before include "Cattle round-up" , "Wild West contest" , "Annually" , "A bunch of cowboys, showing" , "show with mounting excitement" .)