tailspin

noun

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

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

2. (figuratively)A severe mental or emotional collapse; emotional breakdown.

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

3. (figuratively)Any sharp, sustained, often uncontrollable descent or decline.

   “The present stock tailspin proves bankruptcy is imminent.”

   “But I was reading a statement that either you made or was part of your movie, “An Inconvenient Truth”, and it said we have just 10 years to avert a major catastrophe that could send our entire planet into a tailspin of epic destruction involving extreme weather, floods, droughts, epidemics and killer heat waves beyond anything we have ever experienced.”

   “St. Louis, the fourth-largest U.S. city in 1900, is fading fast […] . Jobs, and airline, an educated population—all gone or in a tailspin.”

verb

1. Of an aircraft: to go into a rapid, uncontrollable descent in a steep spiral.
2. (figuratively)To go into a sharp, sustained, often uncontrollable descent or decline.