perjury
noun /ˈpɜːdʒəri/
  /ˈpɜːrdʒəri/
 [uncountable] (law)- the crime of telling a lie in court after you have sworn to tell the truth
- to commit perjury
 - The defence witnesses were found guilty of perjury.
 
Word Originlate Middle English: from Anglo-Norman French perjurie, from Latin perjurium ‘false oath’, from the verb perjurare ‘swear falsely’, from per- ‘to ill effect’ + jurare ‘swear’.