ḥamets

The picture behind this word is souring, not simply swelling. Dough left standing goes sour as it ferments, and the taste changes along with the texture. Hebrew names that whole change with one word, so the risen loaf and the sour taste belong to the same idea.

Most of its uses sit in a single scene, the night Israel left Egypt. The people carried their dough out before it could ferment (Exodus 12:34), baked it flat because it had not risen (Exodus 12:39), and were told to keep leavened food out of their houses for a week (Exodus 12:19, Exodus 12:20). Hosea draws on the same everyday knowledge for a baker's timing, from kneading the dough until it is ready. Nothing in these passages treats sour dough as evil in itself: it marks ordinary time passing, and the flat bread is what haste produced.

One use turns the picture inward. In Psalm 73:21 the singer says his heart went sour, which ties resentment to fermenting: something left alone too long changes into something bitter. The noun for leavened bread (חָמֵץ) and the word for vinegar (חֹמֶץ) grow from the same image of souring, while the lump of sour dough that starts the process has its own name (שְׂאֹר).

A figure comes up from Edom in Isaiah 63:1 with his clothing described by this word, and the picture is of cloth soaked a strong red. The lines that follow show why: he has been treading a winepress alone, and the juice has spattered his garments. Read that way, the word names the color of a stain rather than a dye chosen for a robe.

Nothing else in the Hebrew Bible uses the word this way, so its sense here rests on this one verse and the scene around it. Hebrew already has an ordinary word for being red (אָדֹם), which is part of what makes this rarer choice worth noticing.

Psalm 71:4 asks God for rescue from three sorts of people, and this word names the last of them: someone who squeezes and crushes whoever is weaker. It stands beside a word for a person who twists what is right, so the two together sketch a man who does harm and calls it justice.

This is the only place the word is used this way, and it is the hardest use to pin down. Hebrew has a common verb for doing violence (חָמַס) whose spelling differs by a single letter, and some scholars think that is the word actually intended here. Either way the person described is the same, a violent man the singer wants to be delivered from.