illegitimate vs whoreson

illegitimate and whoreson both are nouns.

Word	Noun	Adjective	Verb	Adverb
illegitimate	Yes	Yes	No	No
whoreson	Yes	No	No	No

As nouns, illegitimate and whoreson are synonyms defined as:

illegitimate and whoreson: the illegitimate offspring of unmarried parents

Other synonyms of illegitimate include bastard, by-blow, illegitimate child, love child.

illegitimate (noun)	whoreson (noun)
the illegitimate offspring of unmarried parents	the illegitimate offspring of unmarried parents
	insulting terms of address for people who are stupid or irritating or ridiculous

illegitimate (adjective)	whoreson (adjective)
of marriages and offspring; not recognized as lawful
contrary to or forbidden by law