economy vs efficiency

economy and efficiency both are nouns.

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

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

economy (noun)	efficiency (noun)
an act of economizing; reduction in cost	skillfulness in avoiding wasted time and effort
frugality in the expenditure of money or resources	the ratio of the output to the input of any system
the efficient use of resources
the system of production and distribution and consumption