atrabiliously /ˌætɹəˈbɪli.əsli/ adverb1 •In an atrabilious (melancholy or ill-natured) manner; grumpily, irritably, morosely.I atrabiliously drew on my trousers, and grumbled furiously at the stupidity of my Highland valet. — 1854 formsmore atrabiliously · most atrabiliously