vitriol

noun

Any of various sulfates of metals, such as ferrous sulfate, zinc sulfate, or copper sulfate.

Bitterly abusive feeling or expression.

transitive verb

To expose or subject to vitriol.

noun

Sulphuric acid, or one of many of its compounds, which in certain states have a glassy appearance.

Ferric sulphate: same as colcothar. Also called vitriol of Mars.