Servant - i. e., A slave, whose obedience is reluctant. He may "understand" the words, but they produce no good effect. There is still lacking the true "answer" of obedience.

A (e) servant will not be corrected by words: for though he understandeth he will not answer.
(e) He who is of a servile and rebellious nature.

A servant will not be corrected by words,.... Not by them only, especially one that is of a servile, surly, and untractable disposition; otherwise a good servant, and well disposed to his master, and willing to serve him, and promote his interest, a word is sufficient for such an one; when he is bid to go, he goes; or to come, he comes, Matthew 8:9; or if he has done wrong, and his fault is told him, he will amend another time; whereas a rough ill natured servant will not regard words, but must have blows to correct him;
for though he understand; what his master says, and what is his will, and knows he has done wrong, and ought to do otherwise, which is an aggravation of sin:
he will not answer; own his fault and promise to do better for the future; through the surliness of his nature, and contempt of his master, whom he does not think worthy of an answer: so the Vulgate Latin version renders it, "he despises to answer"; thus Job was used by his servants, Job 19:16; There is an answering which is forbidden servants, Titus 2:9; but this what becomes them, and is expressive of their respect and reverence to their masters, and their ready, hearty, and cheerful obedience to them; and which especially should be in Christian servants to Christian masters, 1-Timothy 6:1.

Here is an unprofitable, slothful, wicked servant; one that serves not from conscience, or love, but from fear.

A servant--who lacks good principle.
corrected--or discovered.
will not answer--that is, will not obey.

From the discipline of the people this series of proverbs again returns to the discipline of home:
19 With words a servant will not let himself be bettered;
For he understandeth them, but conformeth not thereto.
The Niph. נוסר becomes a so-called tolerative, for it connects with the idea of happening that of reaching its object: to become truly bettered (taught in wisdom, corrected), and thus to let himself be bettered. With mere words this is not reached; the unreasonable servant needs, in order to be set right, a more radical means of deliverance. This assertion demands confirmation; therefore is the view of von Hofmann (Schriftbew. ii. 2. 404) improbable, that 19b has in view a better-disposed servant: supposing that he is intelligent, in which case he is admonished without cause, then the words are also lost: he will let them pass over him in silence without any reply. This attempted explanation is occasioned by this, that מענה can signify nothing else than a response in words. If this were correct, then without doubt its fundamental meaning would correspond with כּי; for one explains, with Lwenstein, "for he perceives it, and may not answer," i.e., this, that a reply cut off frustrates the moral impression. Or also: for he understands it, but is silent - in praefractum se silentium configit (Schultens); and thus it is with the ancients (Rashi). But why should not ואין מענה itself be the expression of this want of any consequences? מענה cannot certainly mean humiliation
(Note: The Syr. and Targ. also think on ענה, for they translate: "for he knows that he receives no strokes.")
(Meri, after Exodus 10:3, הכנעה), but why as an answer in words and not also a response by act (Stuart: a practical answer)? Thus the lxx ἐὰν γὰρ καὶ νοήσῃ, ἀλλ ̓ οὐχ ὑπακούσεται, according to which Luther: for although he at once understands it, he does not yet take it to himself. That מענה tahT . may mean obedience, the Aram. so understood, also at Proverbs 16:4. It denoted a reply in the most comprehensive meaning of the word, vid., at Proverbs 16:1. The thought, besides, is the same as if one were to explain: for he understands it, and is silent, i.e., lets thee speak; or: he understands it, but that which he perceives finds no practical echo.

A servant - Who is so not only in condition, but also in the temper of his mind, disingenuous, and stubborn. Words - By mere words. Tho' - Though he know thy mind, and his own duty.