This term is applied when playing first-person shooter video games, such as Halo, Call of Duty, or another top selling video game title, more specifically Call of Duty.
When someone is using a sniper rifle, and takes longer than approximately 1 second looking down the scope.
A more extreme example is when watching a kill-cam, the player is scoped in from beginning to end, or the player is looking through the scope for the majority or the kill cam.
Player A: "Guys, check out this nice headshot i got for the game winning kill!"
Player B: "Wow that shot wasn't impressive at all, you hardscoped the shit out of that kid."
Player C: "Dude, you're such a noob."