rosh

Behind every use of this word stands a plant: a weed with a bitter, poisonous taste that comes up in fields and vineyards where a good crop should be. Which plant it was is no longer known. Suggestions have ranged from the colocynth gourd to the opium poppy to hemlock, and the biblical writers never describe it, because they did not need to. What they wanted was the taste and the effect: something that looks like food and kills.

From the plant the word reaches easily to the poison itself. Its most common form is a set phrase, "water of poison," the drink the prophets say God will hand to a guilty people. The same word also covers what a snake carries in its bite, so it can name a weed in a furrow and the venom of a cobra without any strain.

It rarely travels alone. Again and again it is paired with another bitter word, wormwood (לַעֲנָה), and the pairing shapes how it is heard:

• Moses warns of a root among the people that bears poison and wormwood.
• Jeremiah promises poisoned water and wormwood as the diet of lying prophets.
• The poet of Lamentations sums up his whole misery as wormwood and poison.
• Amos accuses Israel's leaders of turning justice itself into poison.

That last move is where the word does its hardest work. Poison is not only what an enemy pours out; it is what good things become when they are corrupted. A vineyard, a courtroom, a cup of water: each can turn deadly, and this is the word for what it turns into.