From Longman Dictionary of Contemporary Englishmalefactormal‧e‧fac‧tor /ˈmæləfæktə $ -ər/ noun [countable] old-fashioned formalRO someone who does bad or illegal things
Examples from the Corpus
malefactor• Mordovia is the cesspit into which are flushed the malcontents and malefactors of the Union of Soviet Socialist Republics.• At times the officers of the Crown were worsted by large and desperate bands of armed malefactors.• Due to its generous Proportions it was Put to use on malefactors after its original owner had no further use for it.• The justification was to make police patrols more unpredictable to potential malefactors.• It was the utterly excellent Yahweh who told the malefactors to go to hell.• The earl had gone on ahead in order to round up malefactors and provide the court with some impressive numbers for trial.Origin malefactor (1400-1500) Latin malefacere “to do evil” 