Falsus in uno, falsus in omnibus
“False in one thing, false in all.”
Legal maxim
What does “Falsus in uno, falsus in omnibus” mean?
Falsus in uno, falsus in omnibus translates as “False in one thing, false in all.”
Someone who lies about one thing cannot be trusted on anything.
“Falsus in uno, falsus in omnibus” word by word
| Latin | English | Grammar |
|---|---|---|
| Falsus | false | nominative singular masculine of falsus, “false, deceptive”; it describes the person being judged |
| in | in | preposition taking the ablative here: “in the case of” |
| uno | one | ablative singular neuter of unus, “one”; “in one (thing)” |
| falsus | false | nominative singular masculine of falsus, “false”; repeated for emphasis |
| in | in | preposition taking the ablative here: “in the case of” |
| omnibus | all | ablative plural neuter of omnis, “all, every”; “in all (things)” |
How to pronounce “Falsus in uno, falsus in omnibus”
The two pronunciations differ only slightly: omnibus has a short i in Classical Latin but is usually closer to “ee” in Church Latin. Stress falls on FAL in falsus, on OO in uno and on OM in omnibus.
The story behind it
Word for word the maxim reads “false in one, false in all”. The structure is deliberately balanced: the same word falsus opens each half, so the sentence sounds like a rule.
It is a principle from the law of evidence, usually given in this Latin form. It holds that a witness who has knowingly lied about one point may be disbelieved on every other point as well. I could not confirm a single ancient author for the exact wording, so it is best treated as a traditional legal maxim.
In modern courts the rule is no longer applied strictly. Judges and juries may accept part of a witness’s account and reject the rest. Lawyers still cite the phrase when they want to attack a witness’s credibility, and it is also used in everyday talk about trust.
How to use “Falsus in uno, falsus in omnibus”
It suits a caption or essay point about honesty, trust and credibility, or a quote in a discussion of law and evidence. As a tattoo or motto it works for someone who values plain dealing, though the tone is stern.
- Latin
- Falsus in uno, falsus in omnibus
- English
- False in one thing, false in all.
- Source
- Legal maxim
- Era
- Antiquity
- Theme
- Truth
Common mistakes
- It is a legal maxim, not a line from a named Roman author, so avoid attributing it to Cicero or anyone else.
- Do not read it as a law of nature: courts today treat it as a guide to doubt, not a rule that everything a liar says is false.
- falsus is masculine singular. To describe a woman, change both to falsa; to describe a group, use falsi (men or mixed) or falsae (women).
Questions about “Falsus in uno, falsus in omnibus”
What does “Falsus in uno, falsus in omnibus” mean literally?
“False in one, false in all”. In English it is usually put as: if someone is false in one thing, they are false in everything.
Who said “Falsus in uno, falsus in omnibus”?
No single author is reliably named. It is known as a legal maxim from the tradition of Roman and later European law of evidence.
How do you pronounce “Falsus in uno, falsus in omnibus”?
Classically: FAHL-soos in OO-noh FAHL-soos in OM-nih-boos. In Church Latin the last word is closer to OM-nee-boos.
Is “Falsus in uno, falsus in omnibus” a rule courts still follow?
Not strictly. Courts may still doubt a witness who has lied on purpose, but they can accept the parts of the evidence they find reliable.
More to explore
Translation and grammar checked by Latin Quoter · last reviewed November 2026
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