after-burner
An insult that is understood (and sometimes only insulting) long after the delivery.

Not related to After Burner Fart
Mark: "Janet, you're decorative."
Janet: "Thanks Mark!"
Mark: "Never mind."

Hours later...

Janet: "I'm decorative? Like, only good for like, making things pretty and stuff? Owwww, That burns."

Janet thought it was a compliment until she realized Mark was commenting on her mental abilities or lack there of; Mark had insulted her with an After-Burner.