1. To prove deficient or lacking; to perform ineffectively or inadequately: The business is expected to fail to fulfill its promises.
2. To decline, as in strength or effectiveness: The lights in the room seemed to fail as a result of the electric storm which caused the generators to stop working.

1. To beat or to strike with or as if with a stick; that is, to whack with a manual threshing device consisting of a long wooden handle and a shorter, free swinging stick attached to its end: The tourists could see some people on the farm flail the grain to get the seeds out of the husks.
2. To move vigorously or erratically; to thrash about: Because James was afraid of drowning, he started to flail his arms helplessly in the swimming pool.