Dependable friend gets horse (10)
I believe the answer is:
stablemate
'horse' is the definition.
(stablemate is a kind of horse)
'dependable friend' is the wordplay.
'dependable' becomes 'stable' (I've seen this in another clue).
'friend' becomes 'mate' (mate is a kind of friend).
'stable'+'mate'='STABLEMATE'
'gets' acts as a link.
(Other definitions for stablemate that I've seen before include "Blames Tate (anag) - person from the same club" , "One from the same organisation as another" , "colleague in same organization" , "person in same outfit" , "Maybe fellow Arab" .)