excusable neglect
A failure — which the law will excuse — to take some proper step at the proper time (esp. in neglecting to answer a lawsuit) not because of the party’s own carelessness, inattention, or willful disregard of the court’s process, but because of some unexpected or unavoidable hindrance or accident or because of reliance on the care and vigilance of the party’s counsel or on a promise made by the adverse party. [Cases: Federal Civil Procedure 2656; Judgment 362. C.J.S. Judgments § 320.]