In 1 Samuel 14:8, Jonathan says he and his armor-bearer will "discover" themselves to the Philistines: meaning they'll find out something new about them.

1 Samuel 14:8 (KJV) reads: "Then said Jonathan, Behold, we will pass over unto these men, and we will discover ourselves unto them." Jonathan isn't proposing an investigation: he means "we'll step into the open where they can see us." The underlying Hebrew galah means "to uncover, expose, lay bare," and 1611 "discover" tracked that meaning directly: built from "dis-" (undo) plus "cover," to discover something was to strip away its covering.

Proverbs 25:9 uses the word the same old way: "discover not a secret to another" means don't reveal it, not don't find it out. The now-dominant sense, "find something previously unknown," grew out of this older meaning but hadn't taken over by 1611.