“A fool takes no pleasure in understanding, but only in expressing his opinion.” — Proverbs 18:2
The wise person is not necessarily the one who seems to have all the answers. In fact, he will often have plenty of questions, because wisdom is concerned more with wanting to understand than with sharing an opinion.
But to understand requires listening.
So if you see someone who loves to talk more than they care to listen, or someone who has all the answers but never any questions, realize that these are the habits of fools—regardless of how smart or eloquent the person may appear.