This is not to be confused with lying, cheating, stealing or tax evasion.
The most obvious example is the government official who takes bribes (for himself) in making decisions which are supposed to be in the interests of the state. The same can occur in a large company.
The smaller the company gets, the less scope there is for corruption. Corruption cannot exist in a one person company. It is pointless offering someone in a one person company a bribe - they get to keep the money anyway. A single person can lie, cheat or steal, but this is not corruption.
This is another source of diseconomies of scale, and why economies based on small businesses often do better than those based on large bureaucratic organizations (including communism).
Lawyers are corrupt when they claim to be acting in their client's interest, but are simply trying to maximize their money and status.