A term that expresses that target person is extremely insane, with extreme cases of megalomania, multiple personalities, and obsessed with fire. Persons like this should be treated with caution.
"Hey, did you hear what that guy did? He burned down a teacher's house!"
"Yeah, he's such a Pyro."
Guy2: SHUT THE FUCK UP YOU LITTLE BITCH YOU CAN'T EVEN AIM THE ONLY REASON WHY YOU ARE KILLING ME IS BECAUSE YOU'RE PYRO FDHIBTR&GDBXWHuVAGGGAAAAAAAAHHHHHHHHHHHHHHHHHHHHHHHHHHH
Someone who likes to play Team Fortress 2 on Easy Mode. Pyro is the easiest class and it is very common for a noob to get the top score on a map with Pyro. The Pyro's skills are simply holding W and MOUSE1 until everyone in front of you is dead.