Is it ensure, insure, or assure?
late 16c., "pertaining to the Cimmerii," an ancient nomadic people who, according to Herodotus, inhabited the region around the Crimea, and who, according to Assyrian sources, overran Asia Minor 7c. B.C.E.; from Latin Cimmerius, from Greek Kimmerios. Homer described their land as a place of perpetual mist and darkness beyond the ocean, but whether he had in mind the same people Herodotus did, or any real place, is unclear.