Something that is obviously not fancy, but stands as an ironic contrast; it seems quasi-fancy, or like the person actually tried. (The pronunciation is unsure, so the word works best written.)
Jake: I can't believe my suit hasn't arrived yet! The dance is tonight!
Ellis: No problem, dude, borrow my tuxedo t-shirt! You'll be the most fauxncy person there!
Jake: Great, just great. I'll be as fauxncy as a guy in a Jeffersonian wig.