Corruption is a system that starts out good but somehow goes wrong. The word comes from a Latin word meaning "Rotting". Corruption could be a government doing what they say is good, but instead oppress people, or an official doing something wrong. A text that is miscopied, or computer file or computer program which malfunctions or becomes infected with a computer virus, may be called "corrupt". It may also mean an abuse of power, usually for a personal benefit.
Sometimes the term just means bribery.