wrong-headed 
adjective
Having or showing bad judgement; misguided: this approach is both wrong-headed and naive...
- The approach such provisions represent is wrong-headed and ill-considered - and unworthy of a democratic society.
- I think they are often wrong-headed and foolish, but nobody deserves to be indiscriminately beaten because of their political beliefs.
- That naive misunderstanding summarizes the threat posed by this good-hearted, wrong-headed legislation.
Derivatives
wrong-headedly
- She discusses happiness in the Observer, I think about as wrong-headedly as one can get.
- Alas, at nearly 70 minutes, By the Way is overlong and simply too restrained, and too wrong-headedly earnest, to leave more than a marginal impression.
- I'm going to try to convince you that we developers start off a project wrong-headedly.
wrong-headedness
- Disregarding for a moment the incredible hubris of titling a compilation album Music of the Millennium, there's still so much unintentional hilarity here as to make this CD almost fascinating in its wrong-headedness.
- Eventually, the newspaper will stop printing the increasingly vituperative letters to the editor about the wrong-headedness of last week's column and of half of the preceding letters to the editor about it.
- The most striking element of their behaviour has been a capacity to follow every bad decision with a worse one, combining wrong-headedness with moral weakness to create layer upon layer of confusion, embarrassment and opprobrium.