Proverbs 20:14

¹² Ears that hear and eyes that see— the LORD has made them both.

¹³ Do not love sleep, or you will grow poor; open your eyes, and you will have plenty of food.

“Worthless, worthless!” says the buyer, but on the way out, he gloats.

¹⁵ There is an abundance of gold and rubies, but lips of knowledge are a rare treasure.

¹⁶ Take the garment of the one who posts security for a stranger; get collateral if it is for a foreigner.

Do read the surrounding verses too, because the context often says more than a single verse.

Compare

BSB: “Worthless, worthless!” says the buyer, but on the way out, he gloats.
KJV: It is naught, it is naught, saith the buyer: but when he is gone his way, then he boasteth.
WEB: “It’s no good, it’s no good,” says the buyer; but when he is gone his way, then he boasts.
ASV: It is bad, it is bad, saith the buyer; But when he is gone his way, then he boasteth.
DARBY: Bad! bad! saith the buyer; but when he is gone his way, then he boasteth.
BLB: “Bad, bad,” says the one buying, and having gone away himself, then he boasts.

ÅB: Dårlig, dårlig! sier kjøperen; men når han går bort, roser han seg.
OTB: «Det er ikke bra, det er ikke bra!» sier kjøperen, men så går han bort og skryter.
B1930: Dårlig, dårlig! sier kjøperen; men når han går bort, roser han sig.

1 Thessalonians 4:6
and no one should ever violate or exploit his brother in this regard, because the Lord will avenge all such acts, as we have already told you and solemnly warned you.
Read in context