I quote-mined it from myself, as I've thought and written extensively on it.

I'm defending your mocking of the terms,
because I'm pissed off with how people use them too.

"Selfish", in the common colloquial, is like "capitalism", in that it has two opposite meanings that, when thought is put to them, results in the explosion of the common conception, with the end result being that the term has no meaning, by the common conception, and it only makes sense to say "selfish" in terms of whether they are acting in a self-absorbed fashion, or a self-aware and expanded fashion.

Those are the only two directions of the meaning of selfish -
implosionary and violent, or expansive and loving.