Ted's wandering out East with a horse (5)
I believe the answer is:
steed
'a horse' is the definition.
(steed is a kind of horse)
'ted's wandering out east' is the wordplay.
'wandering' indicates an anagram.
'out' means one lot of letters goes inside another.
'east' becomes 'e' (synonyms).
'teds' anagrammed gives 'sted'.
'sted' enclosing 'e' is 'STEED'.
'with' acts as a link.
(Other definitions for steed that I've seen before include "Warhorse" , "Spirited horse" , "Literary term for horse" , "Swift horse" , "Horse, mount" .)