Perdition is mainly a religious concept from Christianity that means hell or eternal damnation. Perdition doesn't sound like a lot of fun.
If you hear someone say "the fires of perdition," they're talking about the fires of hell. Perdition refers to hell, and especially the religious idea of eternal damnation: suffering for an endless period of time after death. You can also use this word for a more earthly kind of suffering. When you have three exams and an essay due on the same day, you might exclaim, "I'm in perdition!" When you see the word perdition, think "suffering"