I'm not fond of that definition for a couple of reasons:

1. praxeologically, all individuals act for personal gain, which is subjective in nature;

2. most private corporations don't have a well-defined governance (aside from the occasional constitution), specially ones that rely on gift/favor-based economies, such as seen in certain tribes. Governments tend to be an exception due their unique legal nature.

Bernie Madoff's case can best described as a Ponzi scheme, a form of massive fraud scheme.

In a sibling comment, I realized that "corruption" isn't a defined crime in most jurisdictions, aside from Brazil, for some reason, so it's kind of wrong of me to say that corruption is legally defined.

Still, my particular peeve here is the implication of immoral conduct without context on LinkedIn's own rules.

That's either the crime of extortion (which is more broad than corruption) or failing to comply with official duties, which will likely result in firing. When I spoke of the crime of corruption, as expanded in a sibling comment, I was referring to a charge labelled "corruption". It seems, under US, there isn't a law against corruption per se, but against variations of fraud, extortion, etc. Unlike Brazil, for instance, where corruption is, specifically, a crime against the public administration. Still, my bad.

I concede that, outside of formal law, one can describe certain deviations of official attributions of private corps.' agents as corruption.

Brazillian law, for instance, defines the crimes of passive and active corruption:

  The Penal Code, in Article 317, defines the crime of passive corruption as "soliciting or receiving, for oneself or for others, directly or indirectly, even if outside the function or before assuming it, an undue advantage, or accepting a promise of such an advantage." [0]

  Active corruption, committed by an outsider, who offers or promises an undue advantage, is provided for in Article 333 of the Brazilian Penal Code. [1]

But, granted, revieweing US and UK law, it seems they don't define "corruption" as a crime (albeit some of the act names do mention corruption). So let's fallback onto the dictionary: [2]

  a: dishonest or illegal behavior especially by powerful people (such as government officials or police officers) : depravity

  b: inducement to wrong by improper or unlawful means (such as bribery)

  c: a departure from the original or from what is pure or correct

Both definition a and c are too ample and, as you put it, "a smorgasbord". Definition b, specially when combined with a, describes something pretty specific: inducement of a powerful agent to wrong by improper or unlawful means, such as bribes.

Embezzlement is better typified under theft. Same goes for most of the others: fraud is fraud, blackmail is blackmail. They may acquire a "corrupt" character when they are done in direct exchange of personal material gains. There are discussions about whether insider trading should be illegal.

Generally speaking, corruption is primarily a crime against public administration because it involves the government, which (supposedly) represents the people. Private companies represent themselves, so they get to (more) trivially decide who is on the line or not.

[0] https://en.wikipedia.org/wiki/Passive_corruption

[1] https://en.wikipedia.org/wiki/Active_corruption

[2] https://www.merriam-webster.com/dictionary/corruption