Stream in gorge to the west (4)
I believe the answer is:
flow
'stream' is the definition.
(synonyms)
'gorge to the west' is the wordplay.
'gorge' becomes 'wolf' (both can mean to eat eagerly).
'to the west' says the letters should be written in reverse (letters written right to left or 'east to west').
'wolf' backwards is 'FLOW'.
'in' is the link.
(Other definitions for flow that I've seen before include "Well forth" , "Run or move like a liquid" , "Move steadily" , "Wolf (anag.)" , "Run smoothly" .)