What makes someone a psychopath rather than a narcissist?

In brief, psychopaths feel no shame or regret. They don’t give a shit what people think of them. They don’t apologise because they don’t care.

Narcissists on the other hand are entirely dependent on what other people think of them and feel intense shame. They don’t apologise because they cannot accept that they are anything other than perfect (even though they probably know at their core that they are anything but). It would probably be more accurate to say that they cannot afford to allow other people to think that they are anything other than perfect.

Both can come across as similar but because have narcissistic behaviour at their core.

Cluster Bs are very complex and difficult to understand