adjective

1. Having no regard; heedless; careless.

Synonyms: irregardless, irrespective

adverb

1. Without attention to warnings or indications of bad consequences.

   “Tatiana knew the meat had passed its expiry date, but she ate it regardless.”

Synonyms: anyhow, anyway, at any rate, come what may, in any case

preposition

1. Paying no attention to; regardless of.