nefariousness nefariously • nefast · · · Info · Definitions · Synonyms · Characters · · nefariousness · · Text Latin · · Script 13 · · Length Definitions · · · (noun) the quality of being wicked. Synonyms: wickedness, vileness, ugliness. · · Noun Definition 1 Synonyms · · · wickedness · · Synonym 1 vileness · · Synonym 2 ugliness · · Synonym 3 Characters · · a latin small letter a U+0061 e latin small letter e U+0065 f latin small letter f U+0066 i latin small letter i U+0069 n latin small letter n U+006E o latin small letter o U+006F r latin small letter r U+0072 s latin small letter s U+0073 u latin small letter u U+0075