nashakh

This is the ordinary word for biting, and its picture is almost always a snake. Again and again it names the strike of a serpent, whether the real snakes that kill in the wilderness, the venomous creatures God warns he will send in judgment, or the hidden viper waiting where least expected. Even the warning against wine draws on it: in the end strong drink "bites like a serpent."

From that vivid image the word stretches to people who prey on others. When corrupt prophets "bite with their teeth," the point is not real teeth but greed, feeding themselves while pronouncing false comfort. When Habakkuk pictures oppressed nations rising against their oppressor, they "bite" him in turn.

The stretch from a snake's fangs to human exploitation is short and deliberate, and it is the same instinct that gave rise to the second, separate use of this word for charging interest (see the meaning below): interest, too, was felt as something that bites the person who owes it.

This use of the word turns up only in one law, the rule in Deuteronomy that an Israelite must not take interest from a fellow Israelite, though interest may be charged to a foreigner. The verb covers both sides of the transaction: causing someone to pay interest (lending at interest) and paying it.

The same word that means "to bite" is used here on purpose. Interest was pictured as something that bites the borrower, gnawing away at a person already in need. The related noun (נֶשֶׁךְ) names that "bite" as the interest itself. The concern of the law is not commercial banking but protecting a neighbor in hardship from being consumed by debt.