misconceive

To misunderstand.

• 1694, William Congreve, The Double-Dealer Nay, misconceive me not, madam, when I say I have had a gen'rous and a faithful passion, which you had never favoured, but through revenge and policy.

To judge or plan badly, typically on the basis of faulty misunderstanding.

• HS2 has never had that. It was missold, misnamed and misconceived. It was promoted as a piece of engineering, rather than as a vital part of the railway.