Green’s Dictionary of Slang

epic adj.

remarkable.

1988		A. Hollinghurst Swimming Pool Library 221: I was by far the most attractive person in the room, and I wanted something ravishing and epic .
2008		Urban Dict. 10 July 🌐 Listen to this song it’s so epic .
2012		J. Fagan Panopticon (2013) 222: Jumping out into empty space [...] The buzz is fucking epic.

In derivatives

epically (adv.)

in a remarkable manner.

1988		A. Hollinghurst Swimming Pool Library 54: A very well-hung kid [...] brought me off epically during the next film .
2012		R.A. Dickey Wherever I Wind Up 11: It’s hard to get baseball fans in Texas to boo you, but I have done it, with a pitching line that isn’t just bad, but epically bad.