There are many definitions of corruption, but the most common definition is:
The abuse of entrusted authority for private gain.
Corruption crosses all sectors – public, private, and social. Corruption comes in many forms such as bribery and embezzlement, but also includes other practices that do not involve money, like unfair favoritism and nepotism. Each form of corruption gives undue and illicit advantages and benefits.
Also, corruption can be found at all levels; both at a high political and business level (“grand corruption”) and as a part of the daily lives of the common people like small bribes, skimmed paychecks, absentee employees and nepotism in bureaucratic appointments (“petty corruption”). Common to all corruption practices is a violation of trust, an undermining of the common good or interest of the community or society.
Corruption is not an isolated phenomenon found within one specific institution, sector or group – it is pervasive and entrenched in all levels of society. Formal laws try to control corrupt activity, but their enforcement is absent or weak. Institutions of accountability also exist but they are ineffective. Public officials abuse power, and are not deterred nor controlled by state-based accountability institutions or other accountability organizations.
For even more definitions and concepts about corruption, see Transparency International’s Interactive Glossary.