Hi tombola, an extract from Dictionary.com
3 [fel] Show IPA
fierce; cruel; dreadful; savage.
destructive; deadly: fell poison; fell disease.
at / in one fell swoop. swoop ( def 5 ) .
1250–1300; Middle English fel < Old French, nominative of felon wicked. See felon
4 [fel] Show IPA
the skin or hide of an animal; pelt.