But as I see it the common notion of selfish (that is the notion refered to by people ) Being "selfish" or "selfless" is:
1) A matter of degree--it is not an all or nothing thing, but has a graduated scale.
2) It is established by means of social norms--perhaps something that NT's have issue with. But ultimately, one has to weigh the benefits of a persons actions for those other than himself/herself, and ultimately "benefit" is subjective.
3) The core of the definition of selvless vs. selfish then, is simply how much actions purposefully benefit others. A simple definition that is in concert with the official definition of "selish":See the difference in bold between self-motivation and selfishness--the disregard for others.1: concerned excessively or exclusively with oneself : seeking or concentrating on one's own advantage, pleasure, or well-being without regard for others