A term used to describe an unsuccesful attempt at achieving a goal, usually with unintended hilarious results. While a 'fail' can be defined as simple disappointment, an 'epic fail' is of monumental proportions. A term most commonly used by keyboard warriors of the internet age that choose to argue on the website Youtube.com, whose lives could be summed up as an 'epic failure'
Youtube faggot: OMG your such a n00b you got pwned what an epic fail!
Human: Kill yourself.