Oligopolistic rhymes with:
holistic, antiballistic, ballistic, capitalistic, dualistic, fatalistic, feudalistic, holistic, idealistic, imperialistic, individualistic, jelisic, journalistic, legalistic, materialistic, monopolistic, moralistic, nationalistic, naturalistic, novelistic, paternalistic, pluralistic, pugilistic, realistic, ritualistic, sensationalistic, simplistic, socialistic, stylistic, surrealistic, unrealistic