Etymology From Middle English bestely, bestly, equivalent to beast + -ly. Compare West Frisian bistachtich (“beastly”), Dutch beestachtig (“beastly”), German biestig (“beastly”).
1
UK Pertaining to, or having the form, nature, or habits of, a beast.
2
UK Similar to the nature of a beast; contrary to the nature and dignity of human beings.
And all the time, whenever we went to the Cedars, there was all sorts of silly fuss going on about the beastly wedding; boxes coming from London with hats and jackets in, and wedding presents—all glassy and silvery, or else brooches and chains—and clothes sent down from London to choose from.1904, E[dith] Nesbit, “(please specify the page)”, in New Treasure Seekers, London: Ernest Benn, →OCLC:
“Yes, I’ve got the most beastly headache.”1920, Agatha Christie, The Mysterious Affair at Styles, London: Pan Books, published 1954, page 58:
"If you saw the care she takes over hoisting her beastly old carcass up and down those stairs, you could make a sure bet against her having another accident there."1950, Norman Lindsay, Dust or Polish?, Sydney: Angus and Robertson, page 165:
4
UK, Slang Of computer hardware or motor vehicles etc.: ostentatiously powerful.
In addition to a Core i7-860 with a full-sized heatsink and 4GB of DDR3 RAM, the company showed its SUGO SG07 housing today's most beastly graphics card, the dual-GPU Radeon HD 5970, which is about 30cm long.2010 January 11, Matthew DeCarlo, “Silverstone mini-ITX case can fit Radeon HD 5970”, in TechSpot:
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, March 21, Tycho de Feijter, “Hummer H2 is a Big Black Beast in the Rain in China”, CarNewsChina.com
1 more example
Huawei’s Mate 20 phones have instantly become the best iPhone XS rivals out there, at least on paper, and the high-end model is easily the most beastly Android phone the world has seen so far.2018 October 16, Chris Smith, “Huawei just unveiled the most beastly Android phone the world has ever seen”, in BGR:
Etymology From Middle English bestely, bestly, equivalent to beast + -ly. Compare West Frisian bistachtich (“beastly”), Dutch beestachtig (“beastly”), German biestig (“beastly”).
Beastly he threwe her downe, ne car'd to spill / Her garments gay with scales of fish that all did fill.1590, Edmund Spenser, “Book III, Canto VIII”, in The Faerie Queene. […], London: […] [John Wolfe] for William Ponsonbie, →OCLC:
They have insulted me most beastly. Moreover, they are, everyone of them, black-satan filthmen.1901, The Literary World, volume 63, page 35:
"I'm beastly sorry, Wynn, old man," he muttered. "I ought to have remembered."1923, Ernest Bramah [pseudonym; Ernest Brammah Smith], “(please specify the page)”, in The Eyes of Max Carrados, London: Grant Richards, →OCLC:
The baths were mostly tiled showers, with an endless variety of spouting mechanisms, but with one definitely non-Laodicean characteristic in common, a propensity, while in use, to turn instantly beastly hot or blindingly cold upon you, depending on whether your neighbor turned on his cold or his hot to deprive you of a necessary complement in the shower you had so carefully blended.1955, Vladimir Nabokov, Lolita: