κρυφῇ
(prop. -ῆ, Rec.; later spelling is due to assimilation to dat.; cf. εἰκῆ),
adv.,
[in LXX chiefly for סתר;]
secretly, in secret: Eph 5:12.†
G. Abbott-Smith's A Manual Greek Lexicon of the New Testament
κρυφῇ
(prop. -ῆ, Rec.; later spelling is due to assimilation to dat.; cf. εἰκῆ),
adv.,
[in LXX chiefly for סתר;]
secretly, in secret: Eph 5:12.†