nonregent
/ˈnɒnrɪˌdʒɛnt, -ˌdʒɛnt/Definitions
1. noun
A person who is not a ruler, especially a king or monarch.
“The nonregent council governed the kingdom until the rightful ruler was found.”
2. adjective
Not regent or not functioning as a ruler.
“The nonregent period of the kingdom was marked by power struggles and instability.”