Tanking in sports refers to the practice of intentionally fielding non-competitive teams to take advantage of league rules that benefit losing teams. This is a much more common practice in American sports leagues as international sports leagues typically penalize poor performers.

What does it mean when someone is tanking?

The definition of tanked is slang for drunk or intoxicated. When you have had 10 beers, this is an example of a time when you are tanked.

What does it mean when a stock is tanking?

To tank meaning : (Informal) To suffer a sudden decline or failure: The stock market tanked yesterday. ( The Free Dictionary)