oligarchic

Concise Oxford English Dictionary © 2008 Oxford University Press:
oligarchy/ˈɒlɪɡɑːki/

▶noun (pl. oligarchies) a small group of people having control of a country or organization.

■ a country governed by an oligarchy.

– derivatives
oligarchic adjective,
oligarchical adjective,
oligarchically adverb.

– origin C15: from Gk oligarkhia, from oligoi ‘few’ + arkhein ‘to rule’.