parting shot

noun1

1. •
   An insult or barbed comment issued as the speaker departs or the conversation comes to an end.

   • 22 March 2012, Scott Tobias, AV Club Cabin Boyhttp://www.avclub.com/articles/cabin-boy,71269/ When news arrives that the school must graduate Nathanial to official “Fancy Lad” status early and put him on the Queen Catherine first class to run the Mayweather in Hawaii, the headmaster dutifully complies, but Nathanial gets in a few parting shots on his way out the door.