Acrimonious, a.
Etymology: [Cf. LL. acrimonious, F. acrimonieux.]
1. Acrid; corrosive; as, acrimonious gall. [Archaic] Harvey.
2. Caustic; bitter-tempered' sarcastic; as, acrimonious dispute, language, temper.
Shades of meaning
Fernald has no entry of its own for acrimonious; he lists it under bitter, morose.
He lists it without comment; the entries above explain its neighbors.