raper vs assailant

raper and assailant both are nouns.

Word	Noun	Adjective	Verb	Adverb
raper	Yes	No	No	No
assailant	Yes	No	No	No

As nouns, assailant is a hypernym of raper; that is, assailant is a word with a broader meaning than raper:

Other hypernyms of raper include aggressor, assaulter, attacker, criminal, crook, felon, malefactor, outlaw.

raper (noun)	assailant (noun)
someone who forces another to have sexual intercourse	someone who attacks