Acronym that stands for "for the kids", a term used by the sensei and the gakusei that refers to performing a certain task with great enthusiasm and high level of competence for the love of the kids.
Fucking Theater Kids, the perfect moniker to utter under your breath when you are fed up and annoyed with all of the loud-mouthed theater kids shouting and singing loudly and demanding attention everywhere they go.
I really wish that FTK would stop shouting the lyrics to Rent into my ear
First Turn Kill. In Yu-Gi-Oh, certain decks and cards can cause a player to win on their first turn. The most famous would be managing to draw all five pieces of Exodia on your first turn. Otherwise, certain cards, like Canon Soldier, can burn your opponent for damage until they have no life points left.
There's a reason Substitoad is banned. It allowed a lot of FTK shenanigans. People couldn't actually play the game.