A safeword conserns BDSM sexual acts. In BDSM, begging to stop increases pleasure and reality. A safeword is used to actually mean "stop", since screams for stop aren't sincere. The safeword is usually a normal word, like "pink", "banana", or "door" and is determined before starting play.
Jan: Tonight's safeword is "music".
Rob: Oh no! Stop it! Stop it! Stop it!
Jan: Ooh, you've been a naughty boy.
Rob: Please, I'm begging you!
Jan: Alright, enough for tonight you filthy boy.
When a player of a videogame has earned enough experience points to acquire a new level in a skill or skills. Often is accompanied by the ability to weild new weaponry, access new places, or begin new assignments.