wrongheaded
From Longman Dictionary of Contemporary Englishwrongheadedwrong‧head‧ed /ˌrɒŋˈhedɪd◂ $ ˌrɒːŋ-/ adjective WRONG/INCORRECTused to describe an idea, plan, or belief that someone has, that is based on wrong ideas that they are not willing to change —wrongheadedly adverb —wrongheadedness noun [uncountable]Examples from the Corpuswrongheaded• Every aspect of administrative life is influenced by what is most fatuous, wrongheaded and vile.• wrongheaded economic policies• The young man's speech was full of wrongheaded ideas about "the evils of capitalism".