Meaning
What does Sdfg mean?
The term “sdfg” is a name for random keyboard strokes, just like “qwerty” and “asdf”.
Mostly used, when users need to give a name for a something like a file they are saving onto their computers and don’t want to spend time or effort on giving it a proper name or they simply just don’t care.
Sometimes its used as an emote or a meme, for reacting to something on a website or a multiplayer game or twitch.tv stream, to express ones fascination when something unbelievable happens.
“Sdfg” is just like “asdf” which both originated from the PC multiplayer player base, due to these keys being common and easy access for them to type, because their fingers are always near them.
Origin
What's the origin of Sdfg?
The exact origin of the term is unknown, however it has first surfaced on the internet around the time, when the first Call of Duty first-person shooter online game started getting popular in late 2003.
It started out as a mistype of “asdf”, later players started to use this form and “asdf”, when for example they got some impossible shot in a game like Call of Duty.
Spread & Usage
How did Sdfg spread?
“Sdfg” is likely used in multiplayer games and memes commonly around the internet, thanks to the huge popularity of games like League of Legends, DOTA 2, Counter Strike: Global Offensive, and Call of Duty.
Very well known in the PC gaming communities, as when a player rages or gets a huge luck/trick shot, the term/phrase is usually spammed in both lowercase and all caps.

External resources
- Urban Dictionary – sdfg