Poetry right for the river (4)
I believe the answer is:
oder
'river' is the definition.
(River Oder in central Europe)
'poetry right' is the wordplay.
'poetry' becomes 'ode' (ode is a type of poem).
'right' becomes 'r' (common abbreviation).
'ode'+'r'='ODER'
'for the' is the link.
(Other definitions for oder that I've seen before include "river, one in central Europe" , "River flowing into the Baltic" , "waterway" , "Rode around the European river" , "East European river" .)