1. αἴφνης · aiphnēs — Beekes
αἴφνης [adv] ‘suddenly’ (E. ΓΑ 1581, Hp. Int. 39).
*DER More common as well as more archaic is ἐξαίφνης (Hom., Pi. trag., etc.). The adjective αἰφνίδιος (A., Th. Arist.), on the other hand, is more common and more archaic than ἐξαιφνίδιος (PI. Gal.). Adverbial forms αἰφνηδίς, -66v (Hdn.). *ETYM Related to > αἶψα, s.v., and also to » ἄφνω, » ἄφαρ, » ἐξαπίνης, etc. — [Beekes, s.v. αἴφνης, p. 92] 2. αἴφνης · aiphnēs — Frisk
αἴφνης Adv. ‘plötzlich’ (Εἰ. IA 1581, Hp. Int. 39), weit gewöhnlicher und älter ἐξαίφνης (Hom., Pi., Trag., att. Prosa, Arist. u.&.). Umgekehrt ist das Adj. αἰφνίδιος (A., Th., Arist. u.a.) gewöhnlicher und älter als ἐξαιφνίδιος (Pl., Gal.). Andere Bildungen: αἰφνηδίς, -δόν (Hdn.). — Wahrscheinlich mit αἶψα — [Frisk, s.v. αἴφνης, p. 77]
3. αἴφνης · aiphnēs — LSJ
suddenlysuddenly, E. IA 1581, Hp. Int. 39 (αἰφνη-δίς, Hdn. Gr. 1.512; αἰφνη-δόν, Id. Epim. 270). (Prob. cognate with αἶψα rather than with ἄφαρ, ἄφνω).