nefariously

enUK

ne·far·i·ous

N0049600 (nə-fâr′ē-əs)adj. Infamous by way of being extremely wicked.
[Latin nefārius, from nefās, crime, transgression : ne-, not; see ne in Indo-European roots + fās, divine law; see dhē- in Indo-European roots.]
ne·far′i·ous·ly adv.ne·far′i·ous·ness n.
Thesaurus
Adv.1.nefariously - in a nefarious manner or to a nefarious degree; "nefariously involved in a conspiracy"