adj. 1. a. Of or relating to a lower world of the dead. b. Of or relating to hell: infernal punishments; infernal powers. 2. Fiendish; diabolical: infernal instruments of war. 3. Abominable; awful: the infernal racket of the jackhammers. [Middle English, from Old French, from Late Latin īnfernālis, from īnfernus, hell, from Latin, lower, underground; see dher- in the Appendix of Indo-European roots.] in·fernal·ly adv. |
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