burglaryoudaoicibaDictYouDict
burglar: [15] The first trace we have of burglar is as burgulator in 13th-century Anglo-Latin texts, and it appears in Anglo-Norman legal documents of the 15th century as burgler. These point to an unrecorded medieval Latin base *burg- ‘plunder’, which appears in Old French burgur ‘robber’. The verb burgle is a 19thcentury back-formation from burglar.
burglar (n.)youdaoicibaDictYouDict
1540s, shortened from Anglo-Latin burglator (late 13c.), earlier burgator, from Medieval Latin burgator "burglar," from burgare "to break open, commit burglary," from Latin burgus "fortress, castle," a Germanic loan-word akin to borough. The intrusive -l- is perhaps from influence of Latin latro "thief" (see larceny). The native word, Old English burgh-breche, might have influenced the word.