Synonyms For "Infernal" :

1 syllable:

blame, blamed, blessed, cursed, curst, damn, damned, darned

2 syllables:

blasted, deuced, evil, fiendish, goddam, goddamn, goddamned, hellish

3 syllables:

demonic, satanic, unholy

4 syllables:

diabolic

5 syllables:

diabolical