precipitous

adjective

1. Extremely steep; almost vertical, like a precipice.

   B2
   • "The mountain trail was precipitous, with steep drops on both sides."B2
   • "The castle perched on a precipitous cliff above the sea."C1

2. Occurring suddenly or rapidly, especially in a way that is drastic or sharp.

   C1
   • "The company reported a precipitous decline in profits."C1
   • "There has been a precipitous fall in the value of the currency."B2

3. Acting or done hastily without careful thought; rash.

   C1

   formal

   • "He made a precipitous decision to quit his job."C1
   • "Precipitous actions can lead to regret."C2