Set out to get journalist a stallion (5)
I believe the answer is:
steed
'a stallion' is the definition.
(I've seen this before)
'set out to get journalist' is the wordplay.
'out' is an anagram indicator (out can mean wrong or inaccurate).
'to get' means one lot of letters go next to another.
'journalist' becomes 'ed' (short for editor).
'set' anagrammed gives 'ste'.
'ste'+'ed'='STEED'
(Other definitions for steed that I've seen before include "Literary term for horse" , "A mount (poet.)" , "Spirited horse" , "Warhorse" , "Horse, mount" .)