freefall
A very fast, uncontrolled fall through the air or in value.
Freefall is the condition of falling through the air with nothing to slow you down except air resistance. When a skydiver leaps from an airplane, they enter freefall, plummeting toward Earth at incredible speeds until they open their parachute. The rush of wind, the sense of weightlessness, and the ground racing closer all define those thrilling seconds of freefall.
Astronauts in orbit experience a special kind of freefall. They're actually falling toward Earth constantly, but they're also moving forward so fast that they keep missing it, which creates the sensation of floating we often call weightlessness. This is why astronauts drift around the International Space Station: they're in perpetual freefall.
The word also describes any rapid, uncontrolled decline. A company's stock price might go into freefall after bad news, dropping sharply day after day. A student's grades could be in freefall if they stop doing homework. When something is in freefall, it's dropping fast with nothing stopping or slowing its descent. Unlike a controlled descent or a gradual decline, freefall suggests speed, lack of control, and the urgent need for something (a parachute, a solution, a change in direction) to stop the fall before it hits bottom.