- (idiomatic) To become unfavorable; to decrease; to take a turn for the worse.
- I should have walked away from the casino when my luck went south, but I stayed and ended up in the hole.
- He was unconcerned that his health might turn south.
- Yesterday the stock market moved south, ending up on a loss for the day.
- Afterward, when company profits had ventured a bit too far southward, the CFO began to get nervous.
This idiom is constructed with a variety of terms, all consisting of a verb indicating movement and a direction indicating the movement is to the south (southerly, southward, etc.) The exact construction may be modified to fit the circumstances.
- 1967: Bill Sparks, Wild Weasel mission 5 November 1967
- I still had 5 miles (8 km) or so to go to cross the river when all of the controls went south. The bird pitched up, shuddered, rolled right like it was going to spin...
- 2004: Cory Doctorow, Microsoft Research DRM talk
- ...she decided to tape the DVD off to VHS and give that to the kids -- that way she could make a fresh VHS copy when the first one went south.