'Understanding' in the Bible

Promiscuity, wine, and new winetake away one’s understanding.

I will not punish your daughters when they play the harlotOr your brides when they commit adultery,For the men themselves go apart with harlotsAnd offer sacrifices with temple prostitutes;So the people without understanding are ruined.

And Ephraim is become like a silly dove without understanding: they call to Egypt, they go to Assyria.

And now they sin more and more, and have made them molten images of their silver, and idols according to their own understanding, all of it the work of the craftsmen: they say of them, Let the men that sacrifice kiss the calves.