Call into question the integrity or validity of (a practice).
British: Charge (someone) with treason or another crime against the state.
US: Charge (the holder of a public office) with misconduct.
“The most popular tactic is to impeach the credibility of the victim.”
“The physician’s testimony might be impeached, and the report thereby discredited.”
Insolence or arrogance in attitude or tone; cheekiness; forwardness; an instance of this.
Mid 16th century; earliest use found in Wilfrid Holme (d. 1538), author. From (i) Middle French procacité and its etymon (ii) classical Latin procācitāt-, procācitās forwardness, impudence from procāc-, procāx forward, bold, impudent, frivolous + -itās.