The root behind binah is bin, and the ordinary Hebrew preposition bein, between, sits in the same family. Discernment in Hebrew is the ability to tell between: to separate one thing from another and see where the line runs. Not cleverness. Not suspicion. The capacity to distinguish.

I hold that connection as resonance rather than proof; usage governs, and binah earns its meaning in the sentences it appears in. But the sentences agree. When Shlomo could have asked HaShem for anything, he asked for a lev shomea, a hearing heart, to discern between good and evil, 1 Kings 3:9. Between. That is the whole request, and Scripture records that HaShem was pleased he had asked for it ahead of wealth, long life, and the death of his enemies.

Which should settle a nervous question for a lot of believers. Critical thinking is not a secular intrusion on faith. It is binah, and it is the thing the wisest man in the Tanakh asked for first.