Look east for river (4)
I believe the answer is:
aire
'river' is the definition.
(I've seen this before)
'look east' is the wordplay.
'look' becomes 'air' (I've seen this before).
'east' becomes 'e' ('E' can be a synonym of 'east').
'air'+'e'='AIRE'
'for' is the link.
(Other definitions for aire that I've seen before include "Major river of Yorkshire" , "English flower" , "River running through Leeds" , "River of the Yorkshire dales" , "Terrier -- Yorkshire area" .)