Quick answer
Casimir is a boy name with English roots.
Pronunciation: American English /ˈkæz.ɪ.mɪɹ/; British English /ˈkæz.ɪ.mɪə/; French /ka.zi.miʁ/.
Meaning and history
English form of the Polish name Kazimierz, derived from the Slavic element kaziti "to destroy" combined with mirŭ "peace, world". Four kings of Poland have borne this name, including Casimir III the Great, who greatly strengthened the Polish state in the 14th century. It was also borne Saint Casimir, a 15th-century Polish prince and a patron saint of Poland and Lithuania. The name was imported into Western Europe via Germany, where it was borne by some royalty.
Notes and context
Usage: english, french