A Team-Killing Fucktard is commonly encountered in online team-based games, such as Halo (where the term originted).

Normally they are Noobs or Newbs, or just Fucktards in general.

Team-Killing Fucktard can be abbreviated to TKFT. Plural version of the noun is TKFTs. It can also be used as an adjective to describe someone who has killed a team member. There are two definitions of such team-killers,
True Team-Killing Fucktards (TTKFT) and Enraged Team-Killing Fucktards, also known as RageQuit TKFTs (RTKFT or RQTKFT)

Origin:
The origin of the Team-Killing Fucktard originated from popular Halo webseries, Red Vs Blue (RVB) it can also be said that the first recognized TKFT is Caboose from the series, for killing team-captain Church with a tank in the first season. Caboose may not be the first TKFT, but the famous incident has sparked awareness of the dangers that TKFTs present to the online-gaming community and beyond.

the thing that you don’t have when you’re phones percentage is over 20

One who kills (either accidentally or purposefully) a member of his or her own team. Someone who should be killed themself. often used after a lasertag game with friends, during a counterstrike or halo game, or any of the other FPS or gun-related team games.

Somebody who kills a member of his halo team out of boredom or accidentalities

when u kill ur cohorts, team mate, or distraction. AKA, caboose from Red vs. blue

1) Someone who demonstrates the qualities of a fucktard (See definition) before, after, or during the action of killing a teammate in an online game.

2) Caboose, from Red vs. Blue

Caboose from Red Vs. Blue. go to www.redvsblue.com