λάθρῃ
λάθρῃ
λᾰθεῖν
secretly, covertly, by stealth, treacherously, Hom.; λάθρῃ γυῖα βαρύνεται imperceptibly, Il.; so in Attic, Soph., etc.
c. gen. without the knowledge of, unknown to, λάθρῃ Λαομέδοντος Il.; λάθρῃ τῶν στρατηγῶν Hdt.; so in Attic.