illegitimacy vs bar sinister

illegitimacy and bar sinister both are nouns.

Word	Noun	Adjective	Verb	Adverb
illegitimacy	Yes	No	No	No
bar sinister	Yes	No	No	No

As nouns, illegitimacy and bar sinister are synonyms defined as:

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

Other synonyms of illegitimacy include bastardy.

illegitimacy (noun)	bar sinister (noun)
unlawfulness by virtue of not being authorized by or in accordance with law	a mark of bastardy; lines from top right to bottom left
the status of being born to parents who were not married	the status of being born to parents who were not married