Initialism of good going. may be used genuinely or sarcastically.(initialism)
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Use "gg" in a sentence
"Seat 3 said, "gg," as the River card came: the King of Clubs."
"We exchange a few pleasantries, he signs off with 'gg' (it's in-game shorthand for 'Good game'; it's also a way to signal defeat, like waving the white flag of defeat, which is how I would have used it) and I'm left staring at an empty hole in the ground where my once mighty empire stood."
"When it was done, I typed "gg" into the chat box, followed by "wp.""