君くん主しゅ制せい

く

ん

しゅ

せ

い

Meanings

Refers to the system of government where a monarch is the head of state. Often contrasted with 共和制 (republic).

天皇てんのう制せいN2
君主制 is the general term for monarchy of any country, while 天皇制 specifically refers to Japan's imperial institution.
帝てい政せい
君主制 is the general term for monarchy of any kind, while 帝政 specifically denotes rule by an emperor.

共きょう和わN1
共和 (republicanism, as in 共和制) stands in political opposition to 君主制, rule by a monarch.
共きょう和わ制せい
共和制 is government without a monarch, while 君主制 is rule by a monarch as head of state.

君くん主しゅ制せい
Standard kanji spelling for monarchy as a system of government.
君くん主しゅ政せい
Alternate kanji spelling, less common but still used in political contexts.

Compound of 君主 (monarch) and 制 (system). The spelling 君主政 uses 政 (government) instead, with the same reading and meaning.