Meaning of Egui(エグい)

Egui(エグい) means harsh, kind of.
Egui(エグい) if from egumi(えぐ味) which means harsh taste.

Basically, Egui(エグい) is used only in a bad way, but these days, as a slang, young people use it in a good way. We use this word in the sense of awesome or super cool or something.
The basic image of this word in both ways is stimulating, strongly.

In a conversation, sometimes, we just say “Egu(エグっ)”.

Example Conversation

A: Did you watch his super play?
B: Yes! It was soooo Egui(エグい).

A: 彼のスーパープレー見た？
B: 見た！めっちゃエグかった！