TryHard

1. somebody who puts way too much effort into a sport or game, when in reality, they suck
2. a stupid insult used by salty idiots in gaming towards those who have just killed them

1.)

tryhard: *pant* pant* that was one serious game.
person: it was literally just a round of shell shockers...

2.)
g1 gets killed by g2
g1: OMG TRYHARD
g2: technically, you're the tryhard for actually caring about a kill.
g1: SHUT UP NOOB