Didn’t get on a horse evidently for cattle round-up? (5)
I believe the answer is:
rodeo
'cattle round-up?' is the definition.
(I've seen this before)
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for rodeo that I've seen before include "off, sometimes" , "Cattle round-up" , "At which cowboys show their skills" , "stock venue?" , "One should be up for this event" .)