What is the meaning of epic in english?

A long narrative poem written in elevated style, in which heroes of great historical or legendary importance perform valorous deeds. The setting is vast in scope, covering great nations, the world, or the universe, and the action is important to the history of a nation or people.

The word epic means spectacular, very impressive, and awesome in slang.

In literature, it means heroic, majestic, and impressively great.

Example:
Dean: Dude, did you see that guy's backflip?
Mark: No, what about it?
Dean: Man, it was epic!