beastly /ˈbiːstli/adjective 4adverb 2forms 4 adjective4 •Pertaining to, or having the form, nature, or habits of, a beast. •(UK, old-fashioned) Abominable; very unpleasant; hideous.Stop being so beastly to her! •Similar to the nature of a beast; contrary to the nature and dignity of human beings. •(UK, slang) Of computer hardware or motor vehicles etc.: ostentatiously powerful.A very big, very black, and very beastly Hummer H2, Spotted in China in in the rain the great city of Zigong in Sichuan Province. — 2014 adverb2 •Like a beast; brutishly.Beastly he threwe her downe, ne car'd to spill / Her garments gay with scales of fish that all did fill. — 1590 •(informal, old-fashioned) Very much; terribly."I'm beastly sorry, Wynn, old man," he muttered. "I ought to have remembered." — 1923 formsbeastlier · more beastly · beastliest · most beastly