Rider's handhold (4)
I believe the answer is:
mane
'rider's handhold' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for mane that I've seen before include "Hair (of lion)" , "(Lion's) hair on neck" , "Neck hair of an animal" , "Name for hair on horse's neck" , "Animal's neck hair" .)