noun

• (uncountable) The condition of being born out of wedlock; bastardy.
  "So much in those days for royal bastardism."
• (uncountable) A tendency to produce bastards; lack of chastity.
  "A full one-third, and oftentimes more, is expended upon officials and in defraying establishment charges; the remainder is wasted upon the most worthless and vicious of the population, and in sustaining bastardism."
• (uncountable) Racial impurity; that state or quality of being mixed-race.
  "The old man of the family is a mulatto, the mother an Indian; only one of the race has any tolerable pretensions to whiteness of complexion, and this must be the effect of bastardism or of some wild anomalous lusus naturae, or whim of nature, as the philosophers call it, which however has no influence upon his low manners and native stupidity."
• (uncountable) Sexual reproduction involving different species.
  "It is generally well known that all efforts of bastardism to propagate are sterile, and we need not witness the efforts of the horse and mule trying to create a new and better species."