Sui Juris Legal Definition: Latin: one's own law; having full capacity. Related Terms: Alieni juris Thomas Tayler's 1858 dictionary renders the translation of sui juris as: "... of his own right". A person sui juris is one who possesses full civil rights and is not under any legal incapacity. Most adults are sui juris. The counterpart of sui juris in Roman law is alieni juris. In the 1955 version of the Dower Act of the Canadian Province of Alberta; §27. This act applies to all married persons whether or not they have attained the age of twenty-one years, and for the purposes of this Act and every matter or thing done under or by virtue of its provisions, a married person of whatever age shall be deemed to be sui juris." REFERENCES: Dower Act, 1955 R.S.A., Chapter 90. Tayler, Thomas, The Law Glossary (New York: Lewis & Blood, 1858), page 504 Categories & Topics: Dictionary of Latin Law Terms Unless otherwise noted, this page was written by Lloyd Duhaime of Duhaime.org Always looking up definitions? Save time with our search provider (modern browsers only) If you find an error or omission in Duhaime's Legal Dictionary, or if you have suggestion for a legal term, we'd love to hear from you!