Definition
A Latin adjective used in civil and common law contexts meaning base, mean, vile, disgraceful, infamous, or unlawful. Turpis does not appear as a standalone legal term but functions as a qualifying modifier within Latin maxims and compound legal phrases. Its legal significance lies almost entirely in these compounds, where it colors the legal status of an act, person, agreement, or cause of action by marking it as morally degraded or legally void for reasons of public policy.
The most important compounds in legal usage include:
1. EX TURPI CAUSA — "from a base cause." The foundational doctrine, derived from the maxim ex turpi causa non oritur actio (no action arises from a base cause), that bars a plaintiff from recovering in contract or tort when the claim is grounded in the plaintiff's own illegal or seriously immoral conduct.
2. TURPE LUCRUM — unlawful or dishonorable gain. Gain obtained through means that the law regards as base or illicit.
3. TURPE JUDICIUM — a sentence or judgment of infamy; a judicial finding that brands a party as infamous, with attendant civil disabilities.
4. TURPIS ARBITER — a bribed or corrupted judge or arbitrator.
5. TURPIS PERSONA — an infamous person; one disqualified from certain legal acts or testimony by reason of a prior conviction or finding of infamy.
---
Common Language
Modern common usage (Wiktionary): Turpis is not a standard English word. It enters English usage only through legal Latin or classical literature, where it means "base," "shameful," or "disgraceful."
Historical common usage (Webster's 1913): Not entered as an English word. Turpitude — the English derivative — appears, defined as "inherent baseness or vileness of principle, words, or actions; shameful wickedness."
The gap worth noting: English borrowed the concept rather than the word. Where legal sources use turpis as a modifier in Latin phrases, ordinary English legal writing substitutes "turpitude," particularly in the phrase "moral turpitude." Researchers moving between historical Latin-inflected sources and modern English-language cases must track this substitution. The Latin compounds containing turpis and the English phrase "moral turpitude" overlap in concept but are not interchangeable in doctrine.
---
Common Confusion
TURPIS vs. TURPITUDE: These are related but not synonymous. Turpis is an adjective appearing inside Latin legal phrases. Turpitude (turpitudo in Latin) is the abstract noun form — the quality of baseness itself — and is the operative word in modern immigration, professional licensing, and character-evidence law. A researcher finding turpis in historical sources should look for turpitude, moral turpitude, or ex turpi causa when tracking the doctrine forward into modern case law.
EX TURPI CAUSA vs. ILLEGALITY DEFENSE: In modern common law jurisdictions, ex turpi causa has largely been absorbed into what courts call the "illegality defense" or "illegality doctrine." The Latin label still appears in older English and Commonwealth decisions. American courts more often reach the same result under policy-based illegality analysis without invoking the Latin phrase.
---
Why It Matters in Research
Turpis is a gateway term. Encountering it in a historical source signals the researcher to a cluster of doctrines — illegality as a bar to suit, moral disqualification, infamy, and public policy limits on contract enforcement — rather than a single rule.
Several traps exist in historical sources. First, the term appears almost exclusively as a Latin modifier, so keyword searches for "turpis" alone will miss most instances where the concept is expressed in English. Parallel searches for ex turpi causa, turpitude, infamy, and illegality are essential. Second, the doctrine of turpis persona — the infamous person stripped of testimonial or civil capacity — has no direct modern counterpart by that name, though its functional descendants appear in impeachment rules and civil disability statutes. Third, Burrill's entry captures a maxim — turpis est pars quae non convenit cum suo toto ("the part which does not agree with its whole is base") — that appears in interpretive and logical contexts unrelated to the moral-infamy cluster; a researcher encountering this maxim in a contracts or statutory interpretation source is in different doctrinal territory than one encountering turpis arbiter in an arbitration dispute.
The Anderson entry directing readers to "causa, ex turpi" is the correct navigational move for most research purposes: the compound ex turpi causa is where the operative doctrine lives, not the bare adjective.
---
Historical Dictionary Support
Black's (1st Ed.) and Burrill agree closely on the core definition — base, mean, vile, disgraceful, infamous, unlawful — and both note that turpis applies to things and persons alike, citing Calvin's Lexicon. Burrill goes further by enumerating compounds: turpis arbiter, turpis persona, turpe judicium, and turpe lucrum, which Black's (1st Ed.) omits. This makes Burrill the more useful source for compound-hunting.
Anderson's entry is minimal, functioning as a cross-reference rather than a definition, but the cross-reference itself is instructive — Anderson treats turpis as derivative material subordinate to the causa entry, reflecting the practical reality that the adjective's legal life exists only through its compounds.
None of the historical dictionaries engage with the downstream English-language development of the doctrine, particularly the moral turpitude line in immigration and character law, or the modern illegality defense in tort and contract. Researchers should treat these dictionary entries as entry points into classical civil law usage and then follow the English derivatives forward through case law.
---
Jurisdictional Note
The ex turpi causa doctrine descended from turpis is most fully developed as named doctrine in English and Commonwealth jurisdictions, where courts still invoke the Latin phrase. American courts apply functionally equivalent illegality rules but rarely use the Latin label. Civil law jurisdictions may approach the underlying public policy questions through separate doctrinal frameworks without using the turpis vocabulary at all.
---