A word made up by YouTuber "0mgItsJosh"
Its the words fantastic + terrific mixed together.
Guy 1: Hey bro, you okay?
Guy 2: Yeah thanks, are you?
Guy 1: Yup I'm totally fantasterific.
Guy 1: Cool dude.
A combination of the words "fantasic" and "terrific" a sarcastic response to something that no one cares about.
A"Hey guess what?! I'm going to florida!"
B"Well is that just fantasterific?"