bastardy vs illegitimacy

bastardy and illegitimacy both are nouns.

Word	Noun	Adjective	Verb	Adverb
bastardy	Yes	No	No	No
illegitimacy	Yes	No	No	No

As nouns, bastardy and illegitimacy are synonyms defined as:

bastardy and illegitimacy: the status of being born to parents who were not married

Other synonyms of bastardy include bar sinister.

bastardy (noun)	illegitimacy (noun)
the status of being born to parents who were not married	unlawfulness by virtue of not being authorized by or in accordance with law
	the status of being born to parents who were not married