The story
- Old French · derived fromfeloneus
- Middle English · inherited fromfelenous(e), felenows, fellenouse, felonous(e), felonows(e), felonus
- English todayfelonous
From Middle English felenous(e), felenows, fellenouse, felonous(e), felonows(e), felonus, from Old French feloneus. By surface analysis, felon (“an evil or wicked person”) + -ous.
Etymology from Wiktionary, CC BY-SA 4.0.