Failed badly or performed poorly; or filled a container with liquid; in gaming, to act as a tank (absorb damage).
From 'tank,' which came from military vehicles. The slang sense of 'failing badly' emerged in the 1980s, possibly from the image of something heavy sinking.
In online gaming, 'tanks' are characters designed to absorb damage—it's one of those video game terms that's become mainstream slang, showing how gaming culture has infiltrated everyday language.
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