late 14c., in reference to the underworld, from Old French enfernal, infernal (12c.), from Late Latin infernalis "of the lower regions," from infernus "hell" (Ambrose), literally "the lower (world)," noun use of Latin infernus "lower, lying beneath," from infra "below" (see infra-). Meaning "devilish, hateful" is from early 15c. For the name of the place, or things which resemble it, the Italian form inferno has been used in English since 1834, from Dante. Related: Infernally.
例文
1. They can 't work in these infernal conditions.
彼らはこのような最悪の条件下で働くことができない。
2.Stop that infernal noise！
そんなに必死に騒ぐな！
3.'Why，I ain 't sich an infernal lubber，after all.
彼は叫んだ。The post office is shut，which is an infernal bore.
郵便局が閉まっていて、本当に憎い。
5.It 's an infernal mischance ; I 've done my best to discourage it.