1. To charge with a crime or misconduct; esp., to formally charge (a public official) with a violation of the public trust (President Nixon resigned from office to avoid being impeached). • Impeaching a federal official, such as the President, the Vice President, or a judge, requires that a majority of the U.S. House of Representatives vote to return at least one article of impeachment to the U.S. Senate, itemizing the charges and explaining their factual grounds. Even if an official is impeached, removal from office does not occur unless two-thirds of the senators vote for conviction.
2. To discredit the veracity of (a witness) (the lawyer hoped that her star witness wouldn’t be impeached on cross-examination). [Cases: Witnesses 311–409. C.J.S. Witnesses §§ 559–775.]
3. To challenge the accuracy or authenticity of (a document) (the handwriting expert impeached the holographic will).