Ignorantia non excusat
“Ignorance is no excuse.”
Legal maxim
What does “Ignorantia non excusat” mean?
Ignorantia non excusat translates as “Ignorance is no excuse.”
Not knowing the rules does not free you from them.
“Ignorantia non excusat” word by word
| Latin | English | Grammar |
|---|---|---|
| Ignorantia | ignorance, not knowing | nominative singular feminine (subject), from ignorantia, “ignorance”, built on ignorare, “to not know” |
| non | not | adverb of negation; it negates the verb that follows |
| excusat | excuses, frees from blame | third person singular present indicative active of excuso, “I excuse”; subject is ignorantia, so literally “ignorance does not excuse” |
How to pronounce “Ignorantia non excusat”
The main differences are in the first word: Classical gives a hard g and a “ti” like tee, while Church Latin gives gn as “ny” and “ti” as tsee. Stress falls on RAHN in ignorantia and KOO in excusat.
The story behind it
Word for word the line says “ignorance does not excuse”, which English renders as “ignorance is no excuse”. It is the short form of the legal maxim “ignorantia legis non excusat”, “ignorance of the law does not excuse”.
The principle is much older than the wording. Roman jurists already discussed when ignorance of law or of fact could count in a person’s favour, and the fuller maxim took its familiar form in the legal learning of the Middle Ages. It has no single author or source.
Today the idea is a basic rule of many legal systems: you cannot escape liability just because you did not know the law. The short form is often used outside the courtroom for any case where not knowing the rules is no defence.
How to use “Ignorantia non excusat”
It suits a legal or law-school setting, a motto for someone who values knowing the rules, or a pointed caption about taking responsibility. It also works as a dry office-door or desk sign about reading the instructions.
- Latin
- Ignorantia non excusat
- English
- Ignorance is no excuse.
- Source
- Legal maxim
- Era
- Middle Ages (legal)
- Theme
- Justice
Common mistakes
- The short form drops legis (“of the law”). The full maxim is “ignorantia legis non excusat”, and the fuller version is the more precise one.
- It is a legal principle, not a moral claim. Many legal systems do recognise some exceptions, for example certain mistakes of fact, so it is not absolute everywhere.
- Do not read ignorantia as a person. It is an abstract noun in the nominative, and it is the thing doing the (non-)excusing.
- Because it is a legal maxim, it has no single ancient author. Attributing it to a named Roman writer is unsupported.
Questions about “Ignorantia non excusat”
What does “Ignorantia non excusat” mean literally?
“Ignorance does not excuse.” The usual English is “ignorance is no excuse”, meaning not knowing the rules does not free you from them.
Who said “Ignorantia non excusat”?
No one person. It is a legal maxim, a shortened form of “ignorantia legis non excusat”, which developed in medieval legal tradition from older Roman legal ideas.
What is the full version of “Ignorantia non excusat”?
The full maxim is “ignorantia legis non excusat”, “ignorance of the law does not excuse”. The short form leaves out legis, “of the law”.
How do you pronounce “Ignorantia non excusat”?
In Classical Latin: ig-noh-RAHN-tee-ah nohn eks-KOO-saht. In Church Latin: een-yoh-RAHN-tsee-ah nohn eks-KOO-saht.
More to explore
Translation and grammar checked by Latin Quoter · last reviewed November 2026
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