market economy vs economy

market economy and economy both are nouns.

Word	Noun	Adjective	Verb	Adverb
market economy	Yes	No	No	No
economy	Yes	No	No	No

As nouns, economy is a hypernym of market economy; that is, economy is a word with a broader meaning than market economy:

market economy: an economy that relies chiefly on market forces to allocate goods and resources and to determine prices
economy: the system of production and distribution and consumption

Other hypernyms of market economy include economic system.

market economy (noun)	economy (noun)
an economy that relies chiefly on market forces to allocate goods and resources and to determine prices	an act of economizing; reduction in cost
	frugality in the expenditure of money or resources
	the efficient use of resources
	the system of production and distribution and consumption