To impeach means to formally accuse a government official, especially a president, of serious wrongdoing while they're in office. It's not the same as removing them from their job: impeachment is more like bringing charges against them, similar to how a person might be charged with a crime in court.

In the United States, the House of Representatives has the power to impeach a president by voting on whether the evidence of wrongdoing is serious enough to bring charges. If the House votes to impeach, the case then moves to the Senate, which holds a trial to decide whether to actually remove the president from office. Think of it like this: impeachment is the accusation, and the Senate trial determines the consequence.

Several U.S. presidents have been impeached, including Andrew Johnson in 1868, Bill Clinton in 1998, and Donald Trump in 2019 and 2021. None of them were removed from office by the Senate, though Richard Nixon resigned in 1974 before the House could vote to impeach him.

The word can also mean to question someone's honesty or credibility, like when a lawyer tries to impeach a witness's testimony by showing they've been inconsistent or untruthful.