imperialist

adj

1. Of, or relating to imperialism.

noun

1. An advocate of imperialism.

   “"The Japanese imperialists enforced the harshest colonial rule in history over Korea, bringing unspeakably horrible misfortune and sufferings and disasters to the Korean nation," said a spokesman for the Central Committee of the Democratic Front for the Reunification of Korea, according to the state-run Korean Central News Agency.”

2. (attributive, historical, sometimes)An agent or official working on behalf of the Empire of Japan.