Difference between Oligarchic and Oligarchical

OLIGARCHIC vs OLIGARCHICAL: ADJECTIVE

Pertaining to or of the nature of oligarchy or government by a few; administering an oligarchy; administered as an oligarchy or by oligarchs; constituting an oligarchy.

Parasitical, Hegemonic, Tyrannical, Autocratic, Feudal, Undemocratic, Feudalistic, Capitalistic, Dictatorial, Despotic, Totalitarian, Authoritarian, Capitalist, Plutocratic, Oligarchical

Monarchical, Totalitarian, Dynastic, Despotic, Imperialist, Tyrannical, Dirigiste, Capitalist, Capitalistic, Bonapartist, Hegemonic, Collectivist, Monarchic, Plutocratic, Oligarchic

Parasitical, Hegemonic, Tyrannical, Autocratic, Feudal, Undemocratic, Feudalistic, Capitalistic, Dictatorial, Despotic, Totalitarian, Authoritarian, Capitalist, Plutocratic, Oligarchical

Monarchical, Totalitarian, Dynastic, Despotic, Imperialist, Tyrannical, Dirigiste, Capitalist, Capitalistic, Bonapartist, Hegemonic, Collectivist, Monarchic, Plutocratic, Oligarchic

For in ancient Greece elections were considered to be in themselves oligarchic.
The power struggle between oligarchic clans in Ukraine threatens to escalate into an international armed conflict.
By imposing oligarchic regimes in the Greek city states, he secured Spartan domination throughout Greece.
Spartans feared democratic Athenians would spread ideas inimical to martial rule, subverting the oligarchic system.
Sectarian conflict, oligarchic control of public authority, and corruption cannot disappear overnight.
Lulism ideologically disarmed to prevent a coup by the oligarchic allies.
Aristotle and the Problem of Oligarchic Harm: Insights for Democracy.
Novgorod and other oligarchic cities, elected by the town assembly.
USPD plan for oligarchic rule by the council.
In this period, several Latin American countries developed political systems that have been described as oligarchic rule or oligarchic republicanism in the literature.

Although in theory every family was represented in the Grand Council, the de facto situation was somewhat oligarchical.
And in oligarchical States, from the general spread of carelessness and extravagance, men of good family have often been reduced to beggary?
These families are oligarchical in nature and have ruled Nicaragua for generations and their wealth is politically and economically horizontally and vertically integrated.
Robert Michels, Political Parties: A Sociological Study of the Oligarchical Tendencies of Modern Democracy.
Instead I find a troubling lack of transparency coupled with an ostentatious, even oligarchical, attitude.
Are representative governments intrinsically superior to authoritarian, oligarchical or other forms of government?
Argentina, Brazil, Columbia and Uruguay also developed forms of oligarchical democracy.