money vs monetary system

money and monetary system both are nouns.

Word	Noun	Adjective	Verb	Adverb
money	Yes	No	No	No
monetary system	Yes	No	No	No

As nouns, monetary system is a hypernym of money; that is, monetary system is a word with a broader meaning than money:

money: the most common medium of exchange; functions as legal tender
monetary system: anything that is generally accepted as a standard of value and a measure of wealth in a particular country or region

Other hypernyms of money include medium of exchange.

money (noun)	monetary system (noun)
the most common medium of exchange; functions as legal tender	anything that is generally accepted as a standard of value and a measure of wealth in a particular country or region
the official currency issued by a government or national bank
wealth reckoned in terms of money