Abbott-Smith Manual Greek Lexicon
ἄ-δηλος (G82)
2 ἄ-δηλος , -ον ( δῆλος ), [in LXX: Ps 50 (51):6 ( בַּטֻּחוֹת );] unseen , unobserved , not manifest ( Ps 50 (51):6 ): Lk 11:44 . uncertain , indistinct : I Co 14:8 .†
G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain