None but the man "void of wisdom" will show contempt for those about him. The wise man, if he cannot admire or praise, will at least know how to be silent.

He that is void of wisdom - A foolish man is generally abundant in his censures; he dwells on the defects of his neighbor, and is sure to bring them into the most prominent view. But a man of understanding - a prudent, sensible man, hides those defects wherever he can, and puts the most charitable construction on those which he cannot conceal.

He that is void of wisdom despiseth his neighbour: but a man of understanding (f) holdeth his peace.
(f) Will not make light report of others.

He that is void of wisdom despiseth his neighbour,.... Not only in his heart, but by giving him opprobrious language; he speaks contemptibly of him, either because he thinks he is wiser than his neighbour, and therefore calls him fool at every turn; as those who are most destitute of wisdom conceit they have the largest share of it, and despise others; or else because he is richer than his neighbour, as the poor is generally despised by the rich; or because he fancies he is holier than he, as the Pharisee who trusts in himself that he is righteous, and despises others: or a man "that wants a heart" (k), as it may be rendered; that wants a good one, or wants grace in his heart; he despises the counsel and advice, the admonitions and instructions, which his neighbour gives him for his good;
but a man of understanding holdeth his peace: and will not despise his neighbour, or give him ill language, because he is not so wise, or so rich, or so righteous as he; if he cannot speak any good of him, he will not speak evil of him; or he holds his peace, is silent, and will not answer the man void of wisdom, that despises and reproaches him; he will not render railing for railing; when he is reviled he will revile not again; and by so doing he shows himself to he a man understanding, or of intellects; a wise and prudent.
(k) "carens corde", Montanus, Mercerus, Gejerus; "destitutus est corde", Schultens.

A man of understanding does not judge of others by their success.

despiseth--or, "reviles," a course contrasted with the prudent silence of the wise.
holdeth his peace--as if neither hearing nor telling.

There now follow two proverbs which refer to the intercourse of private life.
He who mocketh his neighbour is devoid of understanding;
But the intelligent man remaineth silent.
Proverbs 14:21 is a proverb similarly beginning with בּז לרעהוּ, Proverbs 13:13 is another beginning with בּז לדבר. From this one sees that בּוּז ל (cf. בּזה ל, Isaiah 37:22) does not mean a speaking contemptuously in one's presence; as also from Proverbs 6:30, that contemptuous treatment, which expresses itself not in mockery but in insult, is thus named; so that we do not possess a German [nor an English] expression which completely covers it. Whoever in a derisive or insulting manner, whether it be publicly or privately, degrades his neighbour, is unwise (חסר־לב as pred., like Proverbs 6:32); an intelligent man, on the contrary, keeps silent, keeps his judgment to himself, abstains from arrogant criticisms, for he knows that he is not infallible, that he is not acquainted with the heart, and he possesses too much self-knowledge to raise himself above his neighbour as a judge, and thinks that contemptuous rejection, unamiable, reckless condemnation, does no good, but on the contrary does evil on all sides.

Despiseth - Which he shews by contemptuous or reproachful expressions. Holdeth peace - Forbears all such expressions, and silently and patiently bears those reproaches.