A wild horse on the beach (6)
I believe the answer is:
ashore
'on the beach' is the definition.
(I've seen this in another clue)
'a wild horse' is the wordplay.
'wild' indicates an anagram.
'horse' with letters rearranged gives 'shore'.
'a'+'shore'='ASHORE'
(Other definitions for ashore that I've seen before include "Home for the sailor" , "on terra firma" , "Aground" , "Going on land from sea" , "Hoarse being no longer at sea" .)