exculpation vs impeachment

exculpation

noun
  • The act of exculpating from alleged fault or crime. 

  • That which exculpates; an excuse. 

impeachment

noun
  • The act of impeaching or charging a public official with misconduct, especially if serious, often with the aim of having the official dismissed from office. 

  • A demonstration in a court of law, or before another finder of fact, that a witness was ingenuine before, and is therefore less likely to tell the truth now. 

  • An accusation that a person has committed a crime against the state, such as treason. 

  • The act of calling into question or challenging the accuracy or propriety of something. 

  • The state of being impeached. 

How often have the words exculpation and impeachment occurred in a corpus of books? (source: Google Ngram Viewer )