Debarment Enforcement of Bad Actor Registrants Act of 2021 or the DEBAR Act of 2021 This bill authorizes the Drug Enforcement Administration (DEA) to bar an entity from registering to manufacture, distribute, or dispense controlled substances under certain circumstances. Specifically, the DEA may bar—temporarily or permanently—the registration of an entity that (1) meets or has met any condition for suspension or revocation of the registration, and (2) has a history of prior suspensions or revocations.