to bring a criminal accusation against (somebody)
Brit to charge (somebody) with a serious crime against the state
NAmer to charge (a serving public official) with misconduct
to cast doubt on or challenge the credibility or validity of (e.g. a person's honesty)
The only way out is to impeach the testimony of the witnesses
impeachable adj
impeachment noun
[Middle English empechen from early French empeechier to hinder, from late Latin impedicare to fetter, from in-2 + pedica fetter, from ped-, pes foot]