monarchism

noun

advocacy of a monarch or monarchical rule

Wiktionary

noun

Etymology: Etymology tree French monarchie Proto-Indo-European *-id- Proto-Indo-European *-yéti Proto-Indo-European *-idyéti Proto-Hellenic *-íďďō Ancient Greek -ῐ́ζω (-ĭ́zō) Proto-Indo-European *-mos Proto-Indo-European *-mós Ancient Greek -μός (-mós) Ancient Greek -ῐσμός (-ĭsmós)der. Latin -ismusbor. French -isme French monarchismebor. English monarchism Borrowed from French monarchisme.

Rule by a monarchy.
The advocacy of such a political system.