TAILSPIN

The rapid, uncontrollable descent of an aircraft in a steep spiral.

"The loss of the third engine threw the plane into a tailspin."

A severe mental or emotional collapse; emotional breakdown.

"Just hours after leaving the institution, she suffered another tailspin."

Any sharp, sustained, often uncontrollable descent or decline.

"The present stock tailspin proves bankruptcy is imminent."

Of an aircraft: to go into a rapid, uncontrollable descent in a steep spiral.

To go into a sharp, sustained, often uncontrollable descent or decline.