motherland vs mother country

motherland and mother country both are nouns.

Word	Noun	Adjective	Verb	Adverb
motherland	Yes	No	No	No
mother country	Yes	No	No	No

As nouns, motherland and mother country are synonyms defined as:

Other synonyms of motherland include country of origin, fatherland, homeland, native land.

motherland (noun)	mother country (noun)
the country where you were born	the country where you were born