Tryhard

A player type in TF2 that is mainly a scout, soldier, or demo, that takes the game way too seriously.
Either a streamer with an expensive setup (rare) or a 12-year old scout sweat who stole his mom's credit card (almost always).
Characteristics:
Killing Friendlies
An embarrassing amount of hours on the game
Hyper-expensive unusuals

This is mainly used in a negative connotation against friendly killers.

Endangered Spycrab: wow look at this tryhard killing all the friendlies and taunting
Xx_DABESTSCOUT_xX: THIS IS HOW THE GAME IS MEANT TO BE PLAYED YOU RETARDS
Endangered Spycrab: You are aware this is a 2Fort match.