The dictionary says that a “turnaround” is “an abrupt or unexpected change, esp. one that results in a more favorable situation”. What would be the word for “an abrupt or unexpected change” which is NOT favourable and worsens the situation?
I cannot think of a word but two good expressions would be:
- take a turn for the worse
- take a nosedive
Don't hold me to this but 'upset' as a verb can mean overtun and to become overturned. Because of the way we use it day to day. I feel like it's taken on a mainly pejorative sense.
"Turnarounds" are rarely unexpected, in the context of economics, or the fortunes of people or individual companies. More often, it has the sense of "self-rescue".
I like Jimi Oke's "take a turn for the worse".
I would suggest calling it "a disaster."
For an unexpected change of fortune, I can think of an optimistic word...
Because colloquially we plan for our plans to succeed one can usually use the optimistic term setback OED. Example: "The injury of their star player was a significant setback for the team."