NEPOTISM

Synonyms: Patronage, Clientelism

“Form of favouritism based on acquaintances and familiar relationships whereby someone in an official position exploits his or her power and authority to provide a <…> favour to a family member or friend, even though he or she may not be qualified or deserving”.

Anti-Corruption Glossary (Transparency International), 

https://www.transparency.org/glossary/
See also: The Anti-Corruption Plain Language Guide. (2009). Transparency International,
https://www.transparency.org/whatwedo/publication/the_anti_corruption_plain_language_guide