Dictionary entry

αἰφνίδιος

G. Abbott-Smith's A Manual Greek Lexicon of the New Testament

** αἰφνίδιος (in Lk 21:34, ἐφν- WH; v. M, Pr., 35), -ον

(< αἴφνης = ἄφνως, suddenly), [in LXX: Wi 17:15, II Mac 14:17, III Mac 3:24*;]

sudden, unexpected: Lk 21:34, I Th 5:3.†