IGNORANTIA FACTI EXCUSAT IGNORANTIA JURIS NON EXCUSAT by Law Professor Latin, meaning Ignorance of fact excuses; ignorance of law does not excuse. Related Posts:IGNORANCE OF THE LAWIGNORANTIA LEGIS NON EXCUSATIMPOTENTIA EXCUSAT LEGEMIGNORANTIAINJURIA NON EXCUSAT INJURIAMCRASSUS