Is it ensure, insure, or assure?
1827, "pertaining to or suggestive of the Middle Ages," coined in English from Latin medium "the middle" (see medium (n.)) + aevum "age" (see eon).
A descriptive term for people, objects, events, and institutions of the Middle Ages.
Note: “Medieval” is sometimes used as a term of disapproval for outdated ideas and customs. It may suggest inhuman practices, such as torture of prisoners. (See Inquisition.)