noun
unwritten constitution; uncodified constitution
A constitution based on customs, precedents, and statutes rather than a single codified document. Often contrasted with 成文憲法 (written constitution).
See also: 成文憲法
イギリスには不文憲法がある。
The United Kingdom has an unwritten constitution.
不文憲法と成
Please explain the difference between an unwritten constitution and a written constitution.