Mole takes food beside river (4)
I believe the answer is:
pier
'mole' is the definition.
(mole is a type of pier)
'food beside river' is the wordplay.
'food' becomes 'pie' (pie is a kind of food).
'beside' says to put letters next to each other (I've seen this in other clues).
'river' becomes 'r' (abbreviation).
'pie'+'r'='PIER'
'takes' is the link.
(Other definitions for pier that I've seen before include "Coastal platform" , "Support member" , "Buttress; landing place" , "such as you might see at the seaside" , "A landing stage or promenade" .)