Tajikistan vs Republic of Tajikistan

Tajikistan and Republic of Tajikistan both are nouns.

Word	Noun	Adjective	Verb	Adverb
Tajikistan	Yes	No	No	No
Republic of Tajikistan	Yes	No	No	No

As nouns, Tajikistan and Republic of Tajikistan are synonyms defined as:

Tajikistan and Republic of Tajikistan: a landlocked mountainous republic in southeast central Asia to the north of Afghanistan; formerly an Asian soviet

Other synonyms of Tajikistan include Tadjik, Tadzhik, Tadzhikistan, Tajik.

Tajikistan (noun)	Republic of Tajikistan (noun)
a landlocked mountainous republic in southeast central Asia to the north of Afghanistan; formerly an Asian soviet	a landlocked mountainous republic in southeast central Asia to the north of Afghanistan; formerly an Asian soviet