mid-15c., "wicked, criminal" (implied in feloniously), from felony + -ous. Replaced felonous (mid-14c.) by c. 1600. Felonly (c. 1300) was another variation.
felonious intent
fellow
fellow-feeling
fellowship
felo-de-se
felon
felonious
felony
felsic
felt
fem
fem.
