General definition - Anti-causality. When the desired or expected effect is the only effect NOT achieved by any given cause, this is EPIC FAIL.
Definition as it pertains to Relativity - Failure so monumental in scale that it has the possibility to rupture the space-time continuum by fracturing the light-cone at the point between the causal past and causal present boundaries because there is no possible way the cause could precede any effect within the same spatial reference frame of the observer.
Definition you're most likely to understand - The result of the physical union of your parents.
Bob: "I posted my music on myspace because I wanted to be appreciated by the masses"
Greg: "Oh yeah? What happened?"
Bob: "Turns out my music makes people's ears fall off"
Greg: "Epic fail, no cookie for you!"
Following this conversation, the universe folds in on itself and is oblitera