The definition I keep hearing is "someone who breaks laws a lot" but I feel like that's a stereotype rather than a useful definition.

Is it someone who doesn't have feelings? Is it someone who has trouble feeling feelings? Is it a response to trauma/conditioning or can it be genetic?

Is it possible for someone who has trouble feeling to one day do so uncomplicatedly?

Is Dexter (Lila, from the second season, especially) an accurate portrayal?