The "fool" cannot restrain his wrath; it rushes on "presently" (as in the margin, on the same day, however, uselessly. The prudent man knows that to utter his indignation at reproach and shame will but lead to a fresh attack, and takes refuge in reticence.

A fool's wrath is presently known - We have a proverb very like this, and it will serve for illustration: -
A fool's bolt is soon shot.
A weak-minded man has no self-government; he is easily angered, and generally speaks whatever comes first to his mind.

A fool's wrath is presently known: but (h) a prudent [man] covereth shame.
(h) Who bridles his affections.

A fool's wrath is presently known,.... Having no command of himself, he cannot repress it, nor keep it in; no sooner is he provoked but he shows it in his countenance, and by his words and actions; it is to be seen in the fire of his eyes, in the frowns of his face, in the gnashing of his teeth, and in the stamping of his feet, as well as in the bitter expressions of his mouth: or "a fool's wrath in that day is known" (b); in the same day in which the provocation is given; yea, in the same hour, and in the same moment; he cannot defer showing it for the least space of time; or it is openly known, it is to be seen and observed by everyone: or thus, "a fool is presently known by his wrath" (c); see Ecclesiastes 7:9;
but a prudent man covereth shame; conceals his anger and resentment at any injury done him by words or actions, which if suffered to break out would bring shame and disgrace to him; or he covers the injury itself, the disgraceful words that are spoken of him, and the shameful actions done unto him; he puts up with the contempt that is cast upon him, and bears it patiently; takes no notice of the offence given him, and much less seeks revenge; in which he acts a prudent part, for by so doing he creates less trouble to himself, and gains more credit and reputation from others.
(b) "eo die quo irritatur", Tigurine version; "eodem die", Junius & Tremellius; so Banyus, Merceras, Gejerus. (c) "Cognoscitur ex ira sua", Munster.

A foolish man is soon angry, and is hasty in expressing it; he is ever in trouble and running into mischief. It is kindness to ourselves to make light of injuries and affronts, instead of making the worst of them.

prudent . . . shame--He is slow to denounce his insulters (James 1:19).

The relations of the subject and the predicate are the same as in the preceding verse.
The fool makes known his vexation on the same day [at once],
On the contrary, the prudent man hideth the offence.
Very frequently in these proverbs the first line is only defined by the adducing of the second, or the second holds itself in the light of the first. A post-bibl. proverb says that a man is known by three things: by his כוס (his behaviour in drinking), his כיס (his conduct in money transactions), and his כעס (his conduct under deep inward excitement). So here: he is a fool who, if some injury is done to him, immediately shows his vexation in a passionate manner; while, on the contrary the prudent man maintains silence as to the dishonour that is done to him, and represses his displeasure, so as not to increase his vexation to his own injury. Passionless retaliation may in certain cases be a duty of self-preservation, and may appear to be necessary for the protection of truth, but passionate self-defence is always of evil, whether the injury which is inflicted be justifiable or unjustifiable. Regarding ערוּם, callidus, vid., p. 56; Schultens' comparison of the Greek γεγυμνασμένος is only a conceit in want of better knowledge. Regarding כּסה (only here and at Proverbs 12:23) with מכסּה, as שׁחר (only Proverbs 11:27) with משׁחר, vid., Ewald, 170a. בּיּום signifies on the self-same day = without delay, immediately, and is well translated by the lxx αὐθήμερον. With another object, 16b is repeated in 23a.

Covereth - The shame, or injury done to him, which he conceals and bears with patience.