From Longman Dictionary of Contemporary Englishgo southgo southAmerican English informalBAD if a situation, organization, or set of standards goes south, it becomes very bad although it was once very good It seems like all our moral standards have just gone south. → south
Examples from the Corpus
go south• After four years, their relationship began to go south.• But first he wanted to go south.• His playing time evaporated until just before the break and his numbers also went south.• If so, go south about three miles to Bunker Hill Road.• I must get to the station, go south again.• Motorola stock has been going south since it reached a record 82 1 / 2 last Sept. 29.• Arthur chose Brewyn, a man he could be certain of, then went south to Caerleon well content.• The Marauders going south to play football? 