Leave oar's end out for a duck (9)
I believe the answer is:
goosander
'duck' is the definition.
(goosander is a kind of duck)
'leave oar's end out' is the wordplay.
'leave' becomes 'go' (to go is to depart or leave).
'out' indicates an anagram (out can mean wrong or inaccurate).
'oars'+'end'='oarsend'
'oarsend' anagrammed gives 'osander'.
'go'+'osander'='GOOSANDER'
'for a' acts as a link.
(Other definitions for goosander that I've seen before include "Waterbird" , "Bird" , "duck" .)