beastly
beast-ly
adjective
Extremely unpleasant, disagreeable, or cruel; like a beast.
"What beastly weather we're having!"
adverb
Used as an intensifier meaning 'very' or 'extremely' in a negative sense.
"It's beastly cold outside today."
Thesaurus
Synonyms: brutish, inhumane, bestial, brute, brutal, god-awful, unpleasant, hellish