Beastly
WordNet
adjective
(1) Resembling a beast; showing lack of human sensibility
"Beastly desires"
"A bestial nature"
"Brute force"
"A dull and brutish man"
"Bestial treatment of prisoners"
(2) Very unpleasant
"Hellish weather"
"Stop that god-awful racket"
adverb
(3) In a beastly manner
"She behaved beastly toward her mother-in-law"