take a dive

verb3

1. •
   To decline rapidly.

   • Other broad market gauges took even steeper dives, with the Standard & Poor's 500, which includes financial stocks, falling 9.93%. — 2008
2. •
   To feign a knockout in order to lose intentionally.

   • "You got a fight next weekend. You take a dive in the fourth round, understand?" — 2012
3. •
   To lose or fail intentionally.