Define "corruption"

I was listening the Talk of the Nation the other Day, and Jared Diamond was talking about why some nations succeed and others fail.

http://www.npr.org/2012/05/24/153614162/whats-behind-economic-inequality-between-nations

I understood him to suggest that even if all the other factors for success are in place, corruption can destroy a nation. Now, he was specifically referring to places such as Nigeria where the oil wealth is siphoned off by a few rather than spent for the benefit of the many. And generally, when we think of corruption, we think of countries where there is no law or the law is ignored. We define corruption as rampant bribery, theft of natural resources, routine tax fraud, etc.

But what do you call it when the corruption is masked by law? Certainly, the people at Bain did everything by the book. But when a few profit immensely by moving paper around, isn't that corruption? What did Bain actually produce to benefit the rest of us? What does it do to the value of the US dollar when huge amounts of money are generated with nothing but air to back them up?

I would submit that the astounding income gap developing between the 1% and the 99% is another example of corruption at work.