[Wal.pur.gis Night] n [part trans. of G Walpurgisnacht, fr. Walpurgis St. Walburga d. a.d. 779 Eng. saint whose feast day falls on May Day + G Nacht night] (1823) 1: the eve of May Day on which witches are held to ride to an appointed rendezvous
2: something (as an event or situation) having a nightmarish quality