1. A person who tries hard to impress or tries to be something they are not.
2. What somebody would say to anybody who does a little better than them while playing an online game. The person who calls them a "try hard" probably can't handle getting killed or not getting the first kill of the game so they use this as an insult to feel better.
"Wow look at Nick with his shutter shades, what a try hard!"
imcoollol69: "WOW just because you got the first two kills doesn't make you cool, TRY HARD!"
neoxxy: "Getting two kills doesn't mean shit. Can't handle it then don't play."