alibi vs mitigation

alibi

noun
  • An excuse, especially one used to avoid responsibility or blame. 

  • The plea or mode of defense under which a person on trial for a crime proves or attempts to prove being in another place when the alleged act was committed. 

verb
  • To provide an alibi for. 

  • To provide an excuse for. 

mitigation

noun
  • A reduction or decrease of something harmful or unpleasant. 

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