Used to indicate that a person has definitively beaten the opposition in a given situation. Derived from the game of tennis in which the winner of a match is the player who wins two out of three (for women) or three out of five (for men) sets; each set is made up of a number of games. Thus, the final winning shot is the one that wins the player the point that wins the game that wins the set that wins the match.
"When the prosecutor pulled out the security cam photo showing Darryn in the convenience store with the gun, they had him game, set, match."
by ahrien November 15, 2007
In internet debate, a bluff added at the end of a specious post that is a desperate and hopeless attempt to recover from having been pwned.
Oh you think you're so smart! Well what about blah blah blah, blah blah blah, and blah blah blah? Game, set, match.
by Gruntmaven May 21, 2009
In a heated debate, your side makes a point and then a counter-point is made by the opposing team. You dish out another point only to be countered by....nothing. If enough time goes by and no valid counter-points have been made, or nothing has even been said, then it's time for you to say, "game, set, match."

There's been over 8 seconds of silence from the opposition. You've won. Celebrate.

Synonymous with: For the Win. To school.
A: We should really replace our lightbulbs with compact florescents.

B: How much money do you think it would cost to replace these technologies, and how much e-waste would that produce?

A: This one-time thing? Compact florescents last much longer than typical lightbulbs so we'd actually be saving money and producing less e-waste.

B: ....

A: Game, Set, Match.
by GSMer May 26, 2009
The first (or most popular) definition referencing tennis is most accurate. Tennis however is a gentleman's game and the expression is best used when giving prospers to another player.
You see; Dude come strolled cross the median, must have 9 or 11 hoes trollin' behind, your there with your mediocre mouthpiece and girl number three. All you can say is: "game, set, match pimp."
by Man Veracious December 15, 2020
int. Used to accentuate how completely and thoroughly done someone is with someone else, some thing, a given situation, or the like. Much in the vein of eight ball corner pocket. A derivative of this could be "game, set, and match."
That bitch Charnell has fucked me over for the last time. Fuck her. Game, set, and match.
by Rick June 22, 2005