A consummate example — end of argument! (3,4,4)
I believe the answer is:
the last word
This clue is a double definition.
'a consummate example' is the first definition.
(the last word can mean an ideal or perfect version)
'end of argument' is the second definition.
(Other definitions for the last word that I've seen before include "something really modern" , "Finest example" , "In Hamlet, shoot" , "it's the most up-to-date model" , "Closing remark" .)