נֶתֶרnether

natron, or carbonate of soda, a mineral alkali (Jeremiah 2:22; Proverbs 25:20)

Pronunciation: neh'-ther · Hebrew/Aramaic (Old Testament) · H5427

Same root

נָתַרnâthar · H5425to jump, i.e. be violently agitated; causatively, to terrify, shake off, untie

Where it appears

Appears 2 times in the Bible.

Proverbs 25:20 Singing cheerful songs to a person with a heavy heart is like taking someone’s coat in cold weather or pouring vinegar in a wound.
Jeremiah 2:22 No amount of soap or lye can make you clean. I still see the stain of your guilt. I, the Sovereign Lord, have spoken!

Source: Brown, Driver and Briggs, Hebrew and English Lexicon of the Old Testament (1906), public domain; markup by unfoldingWord, CC BY (github.com/unfoldingWord/Brown-Driver-Briggs-Enhanced).