OXFORD DICTIONARY
Vitriol, n.
1 sulphuric acid or a sulphate, orig. one of glassy appearance.
2 caustic or hostile speech, criticism, or feeling.
copper vitriol copper sulphate. oil of vitriol concentrated sulphuric acid.
ME f. OF vitriol or med.L vitriolum f. L vitrum glass
THESAURUS
Vitriol
acrimony, animosity, animus, bad blood, bitter feeling, bitterness, feud, gall, hard feelings, ill blood, ill feeling, ill will, rancor, soreness, sourness, vendetta, venom, venomousness, virulence