'Understanding' in the Bible

Surely extortion maketh the wise man foolish; and a bribe destroyeth the understanding.

I returned, and saw under the sun, that the race is not to the swift, nor the battle to the strong, neither yet bread to the wise, nor yet riches to men of understanding, nor yet favor to men of skill; but time and chance happeneth to them all.

Yea also, when the fool walketh by the way, his understanding faileth him, and he saith to every one that he is a fool.