Complain of empty gutter river (6)
I believe the answer is:
grouse
'complain' is the definition.
(grouse can mean to complain or grumble)
'empty gutter river' is the wordplay.
'empty' suggests removing the centre.
'river' becomes 'ouse' (Yorkshire river).
'gutter' with its middle taken out is 'gr'.
'gr'+'ouse'='GROUSE'
'of' is the link.
(Other definitions for grouse that I've seen before include "The complaint of a gamebird" , "1D [GAMEBIRD] < having grumble" , "Grumble like game-bird" , "Petty complaint" , "Game bird - beef" .)