superpower vs great power

superpower and great power both are nouns.

Word	Noun	Adjective	Verb	Adverb
superpower	Yes	No	No	No
great power	Yes	No	No	No

As nouns, superpower and great power are synonyms defined as:

superpower and great power: a state powerful enough to influence events throughout the world

Other synonyms of superpower include major power, power, world power.

superpower (noun)	great power (noun)
a state powerful enough to influence events throughout the world	a state powerful enough to influence events throughout the world