Come down from Clydesdale? (8)
I believe the answer is:
dismount
'come down' is the definition.
(dismounting is a kind of coming down)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for dismount that I've seen before include "Get off a horse/bicycle" , "Cease to ride" , "Alight from a horse or bicycle" , "Desert Arab perhaps" , "Get down, from bike or horse" .)