ff15 is a term used in the game League of Legends, ff stands for forfeit and 15 is the time at which it becomes possible to surrender. So ff15 is short for 'surrender at 15 minutes'.
by OppWitSeriousMembers June 2, 2020
FF 15 is a common term that originated from the hit game League of Legends made by the small indie company Riot games. It means to forfeit a game at 15 minutes, the time when you can ff, and has been told in other games by degen league players
by Nabil Lane October 25, 2023