Sentence:  James Smithson was the illegitimate son of the first Duke of Northumberland, third creation. His mother was a lineal descendant of Henry VII. Despite so much blue blood, the <WSD>bar sinister</WSD> seared James Smithson all his life. 
Meaning of the word marked with <WSD> tags:  The state or characteristic of having been born out of wedlock; illegitimacy; bastardy.