IPA: /ˈrɔɪəlɪst/
KK: /ˈrɔɪəlɪst/
A person who supports a government led by a king or queen.
The royalist group organized a rally to promote the monarchy.
Royalist → It is formed from "roy" (from Old French *reial*, meaning royal or pertaining to a king) and "-ist" (meaning a person who practices or is concerned with). A royalist is a person who supports or advocates for a monarchy.
Think of someone who is 'concerned with' ('-ist') the 'royalty' ('roy') — that's why a royalist supports the monarchy.