It is often associated with a third party, having heard said clever comment in another's conversation.
Used in place of other put down-ish phrases, such as, "You just got served" or "Oh snap!" or "PWNED!" etc.
Ryan: That's what she said!
noun: a statement designed to verbally serve someone
neighbor: Hey Griswald, where you gonna put a tree that big?
Griswald: Bend over and I'll show you (...ZING!)
neighbor: You got a lot of nerve talking to me that way.
Griswald (looking at neighbor's wife): I wasn't talking to you (...ZING!)
Whenever someone makes a smart ass comment towards somebody other than you, you are permitted to say "Zing!!!"
Also if you made a smart ass comment towards somebody, you can later refer to it as if you "zinged" them.
Tom: In your mom's bed!
"I zinged that guy pretty good there, lol"
Usually follows a joke at someone else's expense, or when you prove someone wrong.
Can also be used to highlights ones own personal achievment.
Carl: "Hey Mike you're dick. Zing!"
"Tests came back negative.... Zing!"