- fail early 13c., from O.Fr. falir (11c., Mod.Fr. faillir) "be lacking, miss, not succeed," from V.L. *fallire, from L. fallere "to trip, cause to fall;" figuratively "to deceive, trick, dupe, cheat, elude; fail, be lacking or defective." Related: Failed; failing. Replaced O.E. abreoðan. The noun (e.g. without fail) is from late 13c., from O.Fr. faile "deficiency," from falir. The Anglo-French form of the verb, failer, came to be used as a noun, hence FAILURE (Cf. failure).
Etymology dictionary. 2014.