Coach and horses starting for the outback (4)
I believe the answer is:
bush
'the outback' is the definition.
(I've seen this before)
'coach and horses starting' is the wordplay.
'coach' becomes 'bus' (synonyms).
'and' says to put letters next to each other.
'starting' indicates taking the first letters.
The first letter of 'horses' is 'h'.
'bus'+'h'='BUSH'
'for' acts as a link.
(Other definitions for bush that I've seen before include "Shrub; axle lining" , "US president(s) - source of gooseberries" , "A shrub or a modern president" , "Rural African" , "Shrub; Kate --, singer" .)