irredeemably bad or unruly
incorrigible - shameless
Somebody who is deemed ‘incorrigible’ routinely behaves in a contemptible way and is considered beyond correcting or improving. Even though the word implies someone who is hopelessly bad, it can sometimes be used in a light-hearted way to refer to an endearing flaw in a person’s character.
You must be careful doing business with that organization. The person in charge of it is an incorrigible liar.
Oliver is such an incorrigible scoundrel. You never know what he will say or do next!
She’s not an incorrigibly corrupt politician. She just made a poor decision out of desperation.