From Longman Business Dictionary
monopolisticmo·nop·o·lis·tic /məˌnɒpəˈlɪstɪk◂məˌnɑː-/ adjectiveadjECONOMICS controlling or trying to control an industry or business activity completely by not allowing other companies to compete fairlymonopolistic market conditions
Unfair monopolistic practices are prohibited by the Treaty of Rome.