One that fails: a failure at one's career. The condition or fact of not achieving the desired end or ends: the failure of an experiment. The condition or fact of being insufficient or falling short: a crop failure. A cessation of proper functioning or performance: a power failure. Nonperformance of what is requested or expected; omission: failure to report a change of address. The act or fact of failing to pass a course, test, or assignment. A decline in strength or effectiveness. The act or fact of becoming bankrupt or insolvent.