Put out pole with end disappearing in river (6)
I believe the answer is:
depose
'put out' is the definition.
'pole with end disappearing in river' is the wordplay.
'pole' becomes 'post' (I've seen this before).
'with end disappearing' means to remove the last letter.
'in' is an insertion indicator.
'river' becomes 'dee' (River Dee**).
'post' with its final letter removed is 'pos'.
'pos' inserted into 'dee' is 'DEPOSE'.
(Other definitions for depose that I've seen before include "Remove from top position" , "Force out of office" , "Remove from power or bear witness" , "Dethrone; bear witness" , "Oust or unseat" .)