kidnaper vs shanghaier

kidnaper and shanghaier both are nouns.

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

As nouns, shanghaier is a hyponym of kidnaper; that is, shanghaier is a word with a more specific, narrower meaning than kidnaper:

kidnaper: someone who unlawfully seizes and detains a victim (usually for ransom)
shanghaier: a kidnapper who drugs men and takes them for compulsory service aboard a ship

Other hyponyms of kidnaper include crimp, crimper, seizer.

kidnaper (noun)	shanghaier (noun)
someone who unlawfully seizes and detains a victim (usually for ransom)	a kidnapper who drugs men and takes them for compulsory service aboard a ship