Gold coin tossed over river (7)
I believe the answer is:
orinoco
'river' is the definition.
(I know that Orinoco is a river)
'gold coin tossed over' is the wordplay.
'gold' becomes 'or' ('or' is the heraldic name for gold).
'tossed' indicates an anagram.
'over' becomes 'o' (cricket abbreviation).
'coin' with letters rearranged gives 'inoc'.
'or'+'inoc'+'o'='ORINOCO'
(Other definitions for orinoco that I've seen before include "banker" , "resident on Wimbledon Common" , "South-American river" , "Colombia/Venezuela river" , "South American river - lazy Womble" .)