bastardy (n.)youdaoicibaDictYouDict[bastardy 词源字典]
early 14c., "condition of illegitimacy," from Anglo-French and Old French bastardie, from bastard (see bastard). As "begetting of bastards, fornication" from 1570s.[bastardy etymology, bastardy origin, 英语词源]
illegitimate (adj.)youdaoicibaDictYouDict
1530s, "born out of wedlock," formed in English (and replacing earlier illegitime, c. 1500), modeled on Latin illegitimus "not legitimate" (see il- + legitimate). Sense of "unauthorized, unwarranted" is from 1640s. Phrase illegitimi non carborundum, usually "translated" as "don't let the bastards grind you down," is fake Latin (by 1965, said to date from c. 1939) (Carborundum was a brand of abrasives).