bes·tial 
(bĕschəl, bēs-)
(bĕschəl, bēs-)adj.
1. Of or resembling a beast: a bestial roar.
2. Marked by brutality or depravity; brutal or depraved: capable of the most bestial acts imaginable.
[Middle English, from Old French, from Late Latin bēstiālis, from Latin bēstia, beast.]
bestial·ly adv.