The phrase "Revolutionary Proletarian Nucleus" refers to a group of individuals who are actively engaged in promoting revolutionary change. However, this phrase may not always be applicable, and therefore, synonyms such as "radical, militant, or activist" could be used in its place. These synonyms describe individuals who are dedicated to advocating for their beliefs and are willing to take action to achieve their goals. Other synonyms include "rebel, dissident, agitator, revolutionary, and insurgent." Regardless of the term used, the important thing is that there are people who are willing to challenge the status quo and fight for the change they believe in.