Look for shelter by river (4)
I believe the answer is:
leer
'look' is the definition.
(I know that leer is a type of look)
'shelter by river' is the wordplay.
'shelter' becomes 'lee' (as in lee side, the side sheltered from wind).
'by' is a charade indicator (letters next to each other).
'river' becomes 'r' (abbreviation).
'lee'+'r'='LEER'
'for' is the link.
(Other definitions for leer that I've seen before include "Lascivious gaze" , "Lewd look" , "Look lecherously" , "Stare suggestively" , "Suggestive or sneering grin" .)