An offender lacking guilt or remorse and violating social norms is likely suffering from what?

An offender who shows a lack of guilt or remorse and consistently violates social norms is most likely exhibiting characteristics associated with antisocial personality disorder. This disorder is defined by a pervasive pattern of disregard for the rights of others and societal rules. Individuals with this disorder often engage in deceitful and manipulative behavior, lack empathy, and fail to conform to societal expectations. These traits align closely with the behaviors described in the question, making antisocial personality disorder the most fitting diagnosis.

In contrast, narcissistic personality disorder primarily involves an inflated sense of self-importance and a need for excessive admiration, but individuals with this disorder may show some level of guilt or remorse under certain circumstances. Major depressive disorder and bipolar disorder are mood disorders characterized by issues related to emotional regulation, but they do not typically manifest as a lack of guilt and remorse or a disregard for societal norms in the same way that antisocial personality disorder does.