SteveR wrote: The definition of sin is literally 'missing the mark.' And you continue to miss the mark..
Actually, that is only partly true. What about "transgression" and "iniquity"? IOW, sin is transgression of the law - overstepping the mark, and it is also perversion, or twistedness!
But, I'm sure your beloved RCC theology doesn't sit comfortably with these notions being a good semi-pelagian that you are.