People's Republic of China vs Red China

People's Republic of China and Red China both are nouns.

Word	Noun	Adjective	Verb	Adverb
People's Republic of China	Yes	No	No	No
Red China	Yes	No	No	No

As nouns, People's Republic of China and Red China are synonyms defined as:

People's Republic of China and Red China: a communist nation that covers a vast territory in eastern Asia; the most populous country in the world

Other synonyms of People's Republic of China include Cathay, China, Communist China, mainland China, PRC.

People's Republic of China (noun)	Red China (noun)
a communist nation that covers a vast territory in eastern Asia; the most populous country in the world	a communist nation that covers a vast territory in eastern Asia; the most populous country in the world