ignorance in court of law
For example ignorance of a law which has not yet been promulgated. Ignorantia juris non excusat or Ignorantia legis neminem excusat is a Latin maxim which means ignorance of the law does not excuse or ignorance of the law excuses no one. The rationale of this maxim is that if ignorance of law was an excuse then any person charged with a criminal offense or subject of a civil suit can claim that he or she was unaware of the law in question and avoid liability.