konstitucio

The founding document of a state: the law that sits above the laws. A konstitucio says how a country is put together and what its government may not do. The adjective is konstitucia, and kontraŭkonstitucia is unconstitutional, which is a satisfying pile of morphemes for a word English needs a Latin prefix and four syllables of its own to build.

Esperanto has one of its own, and that is the fastest way in.La Fundamento of 1905 is the language's constitution in everything but name: the sixteen rules, the grammar and the base vocabulary that the movement voted never to change. It works exactly as a constitution does. Later decisions have to be compatible with it, the Akademio interprets it rather than rewrites it, and the argument about whether something is laŭfundamenta is the same argument a court has about whether a statute is constitutional. That story is told properly in the Fundamento and the Akademio.

One false seam to close. The -acio at the end is not an Esperanto suffix. Konstituci- is a single borrowed root, exactly like federaci- and civilizaci-, and you cannot peel -acio off and find konstitui underneath. Esperanto imports these whole from the international vocabulary; the visible Latin joints are history, not grammar. Compare procento, which has the same trap in its opening syllables.