'Secret' in the Bible

a man has sexual relations with her and she conceals it from her husband, keeping it secret although she has defiled herself with there being no witnesses against her, but she was caught anyway.

No evil power has effect against Jacob, no secret arts against Israel; at the right time it will be said of Jacob and of Israel, See what God has done!

Now when Balaam saw that it was the Lord's pleasure to give his blessing to Israel, he did not, as at other times, make use of secret arts, but turning his face to the waste land,

And looking on the Kenites he went on with his story and said, Strong is your living-place, and your secret place is safe in the rock.