Abbreviation for the cult indie horror game "Five Nights at Freddy's". It's often referred to in its abbreviated form by members of the fandom wanting to discuss theories about the game's plot, knowing that other fans will know what they mean by using the abbreviation. The sequels to the game can also be abbreviated to "FNAF2", "
FNAF3", "
FNAF4" and "
FNAFSL" for Five Nights at Freddy's: Sister Location.