vitriol

noun

1. (countable, dated, uncountable)Any of various metal sulphates.

   “CRYSTALS of Venus or of copper, called also vitriol of Venus, is copper reduced into the form of vitriol by spirit of nitre, or by dissolving verdegris in good distilled vinegar, till the acid be saturated; it is very caustic and used to eat off proud flesh. It is also used by painters, and manufacturers, and sold under the name of distilled vinegar. See CHEMISTRY.”

2. (countable, dated, uncountable)oil of vitriol (sulfuric acid).
3. (broadly, countable, uncountable)Bitterly abusive language.

   “For days, online forums sparked with outrage against politicians and race organizers, a tone that turned to vitriol against runners, even from some shaming other runners for being selfish.”

verb

1. (transitive)To subject to bitter verbal abuse.
2. (transitive)To dip in dilute sulfuric acid; to pickle.
3. (colloquial, transitive)To vitriolize.