Definition: “To confront (a member of Parliament) with his former utterances as recorded in ‘Hansard’; to prove (a person) to have formerly expressed a different view or opinion.” (Oxford English Dictionary)
Hansardize comes from the name of the printer who for decades published reports of parliamentary proceedings, one Thomas Crown Hansard. The word appears to have never gained much currency outside of the United Kingdom, which is a bit of a pity.
He had seen enough of the process of Hansardizing going on in that House to know it was very disagreeable to be a Hansardee, and, therefore, he would not subject himself to it.
—The Battle for Native Industry (the debate upon the corn laws, the Corn Importation and Customs' Duties bills, and the other financial measures of the government in session 1846), 1846