The M-W dictionary might not be the best source for that definition. The people best disposed to curate the meaning of that word, psychiatrists and psychologists, would characterize psychopaths as being bold, disinhibited, and utterly lacking in empathy or remorse.
In other words, they do what they want, when they want, and don't care about how it impacts anyone else, not during the act, and not after they finish. Correctly believing yourself to be smarter than most other folks is barely a nudge from the normal end of that spectrum.
But if I were to guess, r is probably very slightly positive when correlating genius with psychopathy, psychopathology, and several other "that guy's a little odd" disorders.
In case of psychopathy, or better anti-social personality traits in general, there is some research into this, and it indicates that "genius level" intelligence is a protective factor. So a person with amoral/anti-social traits and very high score on the G factor (I think) is able to compensate, high cognitive abilities can sort of inhibit amoral impulses through sheer brute force of intellect, sort of. This makes sense because anti-social/amoral behaviour is in the general case not very adaptive and beneficial (for each successful psycho, you have vastly more of them leading miserable lives). Also, the relationship is non-linear, it only works for very high levels of intelligence. I'd love to give you some reference, but unfortunately I don't have the literature at hand ATM.
In other words, they do what they want, when they want, and don't care about how it impacts anyone else, not during the act, and not after they finish. Correctly believing yourself to be smarter than most other folks is barely a nudge from the normal end of that spectrum.
But if I were to guess, r is probably very slightly positive when correlating genius with psychopathy, psychopathology, and several other "that guy's a little odd" disorders.