Mongolia vs Mongolian People's Republic

Mongolia and Mongolian People's Republic both are nouns.

Word	Noun	Adjective	Verb	Adverb
Mongolia	Yes	No	No	No
Mongolian People's Republic	Yes	No	No	No

As nouns, Mongolia and Mongolian People's Republic are synonyms defined as:

Mongolia and Mongolian People's Republic: a landlocked socialist republic in central Asia

Other synonyms of Mongolia include Outer Mongolia.

Mongolia (noun)	Mongolian People's Republic (noun)
a landlocked socialist republic in central Asia	a landlocked socialist republic in central Asia
a vast region in Asia including the Mongolian People's Republic and China's Inner Mongolia