Bar Sinister Definition

noun
A heraldic bend or baton sinister, held to signify bastardy. Not in technical use.
American Heritage

Bend sinister.

Webster's New World
A hint or proof of illegitimate birth.
American Heritage
(heraldry, considered nonstandard) A bend sinister or baton sinister in a coat of arms.
Wiktionary

(idiomatic, euphemistic) The state or characteristic of having been born out of wedlock; illegitimacy; bastardy.

Wiktionary
Synonyms: