mortally

Mortally means extremely or fatally, used to describe something that's incredibly bad or likely to cause death.

The word "mortally" can be a bit tricky because it has some other related uses. When you're talking about something being mortal, like when people say "As a mortal, I'm worried about dying", they mean humans are naturally subject to death. In the same way, if something is a mortal blow, it's one that will definitely kill someone or something. But in modern language, "mortally" is more often used to describe something as extremely bad or serious - like mortally offended by a joke.