Horseman needing money: gold sovereign? (7)
I believe the answer is:
centaur
'horseman' is the definition.
(half horse, half man)
'money gold sovereign?' is the wordplay.
'money' becomes 'cent' (eg denomination of dollars).
'gold' becomes 'Au' (Au is the chemical symbol for gold).
'sovereign?' becomes 'r' (I've seen this in other clues).
'cent'+'au'+'r'='CENTAUR'
'needing' is the link.
(Other definitions for centaur that I've seen before include "Fabulous horse-man" , "Mythological horse-man" , "Mythical creature with the head of a man and the body of a horse" , "beast seemingly half human" , "Mythical beast, half horse and half man" .)