Discipline for moral turpitude. What is moral turpitude?

I have commented before how the concept of "moral turpitude" is used inconsistently and how I am still confused as to what it really means.  About two weeks ago, Prof. Ronal Rotunda (Chapman) wrote an excellent short comment on the issue here.  He concludes that "the law may reject “moral turpitude” as a standard too vague to apply, yet some courts continue to apply it, even though those courts have adopted new rules that reject “moral turpitude” as the standard. Go figure."