1. Struck by lightning, the plane fell into a precipitous dive and hit the ground in a massive fireball.
2. overhasty; rash; heedless
2. Never marry in a precipitous manner: this is the most important decision you are ever going to take, so take your time.
praeceps praecipis (steep) (Latin)
You can remember two words like this "He has a PRECIPITATE (without thinking carefully) decision: climb a very PRECIPITOUS cliff"