In a nefarious manner; with extreme wickedness; abominably.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
ad. in a nefarious manner or to a nefarious degree
Word Usage
"And, I say to them, you used the term nefariously, odiously and defensively; now that we use it as a term of endearment you can't have in, that's the restriction of your white supremacist and racist mindset, you got to deal with that."