(n) That moment
in your life when you start letting yourself say "fuck" out loud, accompanying or resulting in a sudden, long-term or
permanent increase in overall propensity to swear.
Typical age at tempus fuckit is between your mid-teens and mid-20s, but it can occur earlier or much later. No specific trigger required, but often follows a recent, persistent increase in the amount of stress in your daily life—learning to drive, experiencing a messy breakup, watching your first group project descend into a death spiral, taking a job in retail, etc. The requisite long-term effect means a tempus fuckit can only be identified well
after the fact.
Children parroting someone else's cursing for
the first time, without knowing what it means, are NOT having their tempus fuckit. An adult who says "fuck" once in their lives and then goes back to their normal selection of oaths has not had a tempus fuckit. The tempus fuckit is an informed, if not deliberate, decision that becomes a habit.
The tempus fuckit as a rite of passage is rather like your first hangover: a thing to joke or commiserate about, but not something to be proud of.