the GNU version of the Collaborative International Dictionary of English
ad. In an acrimonious manner.
The Century Dictionary and Cyclopedia
In an acrimonious manner; sharply; bitterly; pungently.
Word Usage
"Last year's climate-change summit in Copenhagen ended acrimoniously with a last-minute nonbinding accord brokered by the U.S. and China, both of which had traded accusations of diplomatic snubs."