Abbott-Smith Manual Greek Lexicon
λεῖος (G3006)
1 λεῖος , -εία, -εῖον , [in LXX: Ge 27:11 , I Ki 17:40 R ( חָלָק , חַלּוּק ); ὁδὸς λ. , Is 40:4 Α ( בִּקְעָה ); Pr 2:20 12:13 26:23 *;] smooth : opp. to τραχύς , Lk 3:5 (LXX) .†
G. Abbott-Smith, A Manual Greek Lexicon of the New Testament (1922) — public domain