- The definition of nefarious is someone who is known for being very wicked.
An example of nefarious is Adolf Hitler.
nefarious definition by Webster's New World
Origin: Classical Latin nefarius ; from nefas, crime, sin ; from ne-, not plush fas, (divine) law, lawful
nefarious definition by American Heritage Dictionary
Origin: Latin nefārius, from nefās, crime, transgression : ne-, not; see ne in Indo-European roots + fās, divine law; see dhē- in Indo-European roots.
- ne·farˈi·ous·ly adverb
- ne·farˈi·ous·ness noun