diabolic (adj.)

• abominable
• accursed
• animal
• anthropophagous
• appalling
• atrocious
• awful
• bad
• barbaric
• barbarous
• base
• beastly
• bestial
• bloodthirsty
• bloody
• bloody-minded
• brutal
• brute
• brutish
• cannibalistic
• corrupt
• cruel
• cursed
• damnable
• demoniac
• demoniacal
• demonic
• depraved
• devilish
• diabolical
• dreadful
• evil
• execrable
• fell
• feral
• ferocious
• fiendish
• fierce
• flagitious
• foul
• ghoulish
• heinous
• hellish
• hideous
• horrible
• horrid
• ill
• impious
• infernal
• inhuman
• inhumane
• iniquitous
• maleficent
• malevolent
• malicious
• malign
• monstrous
• murderous
• odious
• ruthless
• sadistic
• sanguinary
• sanguineous
• satanic
• savage
• serpentine
• sinful
• sinister
• subhuman
• terrible
• truculent
• unchristian
• uncivilized
• ungodly
• unhallowed
• unhuman
• vicious
• vile
• wicked
• wolfish