hellish; fiendish; diabolical

an infernal plot.

extremely troublesome, annoying, etc.; outrageous

an infernal nuisance.

of, inhabiting, or befitting hell.

Classical Mythology . of or pertaining to the underworld.

adjective

heavenly , otherworldly

adjective

accursed , blamed , blasted , chthonian , confounded , cursed , cussed , damnable , demonic , devilish , diabolical , execrable , fiendish , hellish , lower , malevolent , malicious , monstrous , nether , satanic , subterranean , sulphurous , wicked , diabolic , ghoulish , ogreish , satanical , blessed , bloody , damn , darn , abominable , avernal , awful , bad , chthonic , damned , demoniac , evil , horrible , horrific , mephistophelian , pandemoniac , stygian , tartarean , underworld , vicious