Cathay vs Communist China

Cathay and Communist China both are nouns.

Word	Noun	Adjective	Verb	Adverb
Cathay	Yes	No	No	No
Communist China	Yes	No	No	No

As nouns, Cathay and Communist China are synonyms defined as:

Cathay and Communist China: a communist nation that covers a vast territory in eastern Asia; the most populous country in the world

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

Cathay (noun)	Communist 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