How do you say monarch in Chinese?
— 君主; 君主

Specialized synonyms for monarch in Chinese
emperor皇帝 (huángdì), 帝王 (dìwáng), 天皇 (tiānhuáng)
kingK (kei, kǎi), 凱, 凯 (kǎi)
tsar沙皇 (shāhuáng)