early 13c., "failure, failure to act," from O.Fr. defaute (12c.) "fault, defect, failure, culpability, lack, privation," from V.L. *defallita "a deficiency or failure," pp. of *defallere, from L. de- "away" + fallere "to deceive, to cheat; to put wrong, to lead astray, cause to be mistaken; to escape notice of, be concealed from." The financial sense is first recorded 1858; the computing sense is from 1966.