It is an acronym for Fear, Uncertainty, Doubt. Something has happened, the house is falling apart! Save yourself! Basically, it's a slang term for bad feelings or energy around a cryptocurrency.
It is a tactical act of spreading negative rumors or misleading information through social media and other news platforms that the price of a coin is crashing. This tactic mostly affects newbies who don't know their position and then sell at a lower price.
