noun

• (by extension) The combining of separate races in marriage or breeding; miscegenation.
  "This is a basis for a natural, even though slow, process of regeneration, which gradually eliminates racial poisonings as long as a basic stock of racially pure elements is still present and a further bastardization does not take place."
• (more generally) The creation of an inferior copy or version; corruption, degradation, or debasement.
  "In this manner they viewed traditional aspects of civilization as parts of the legitimate identity of a culture. Consequently, they could interpret religion as one meaningful way for each culture to deal with external reality rather than as a superstitious bastardization of reason."