felonious (adj.)youdaoicibaDictYouDict[felonious 词源字典]
mid-15c., "wicked, criminal" (implied in feloniously), from felony + -ous. Replaced felonous (mid-14c.) by c. 1600. Felonly (c. 1300) was another variation.[felonious etymology, felonious origin, 英语词源]