What does acrimonious mean?
The definition of acrimonious
Ac”ri*mo”ni*ous, a.
Etym: [Cf. LL. acrimonious, F. acrimonieux.]

1 Acrid; corrosive; as, acrimonious gall. [Archaic] Harvey.
2 Caustic; bitter-tempered’ sarcastic; as, acrimonious dispute, language, temper.