To go deep into something.

Hear ye this, O priests; and hearken, ye house of Israel; and give ye ear, O house of the king; for judgment is toward you, because ye have been a snare on Mizpah, and a net spread upon Tabor. And the revolters ARE PROFOUND to make slaughter, though I have been a rebuker of them all. ( Hosea 5:1-2 )

Dictionary of Words from the King James Bible. Public Domain. Copy freely.