kidnaper vs malefactor

kidnaper and malefactor both are nouns.

Word	Noun	Adjective	Verb	Adverb
kidnaper	Yes	No	No	No
malefactor	Yes	No	No	No

As nouns, malefactor is a hypernym of kidnaper; that is, malefactor is a word with a broader meaning than kidnaper:

kidnaper: someone who unlawfully seizes and detains a victim (usually for ransom)
malefactor: someone who has committed a crime or has been legally convicted of a crime

Other hypernyms of kidnaper include captor, capturer, criminal, crook, felon, outlaw.

kidnaper (noun)	malefactor (noun)
someone who unlawfully seizes and detains a victim (usually for ransom)	someone who has committed a crime or has been legally convicted of a crime