Mythical hybrid of man and horse (7)
I believe the answer is:
centaur
(Other definitions for centaur that I've seen before include "Mythical animal, half man and half horse" , "Mythological man-horse" , "Mythic man-horse" , "'Mythical creature, half man, half horse (7)'" , "Mythical creature, half-man, half-horse" .)