frugalness vs thrift

frugalness and thrift both are nouns.

Word	Noun	Adjective	Verb	Adverb
frugalness	Yes	No	No	No
thrift	Yes	No	No	No

As nouns, thrift is a hyponym of frugalness; that is, thrift is a word with a more specific, narrower meaning than frugalness:

frugalness: prudence in avoiding waste
thrift: extreme care in spending money; reluctance to spend money unnecessarily

Other hyponyms of frugalness include parsimoniousness, parsimony, penny-pinching, economy, thriftiness.

frugalness (noun)	thrift (noun)
prudence in avoiding waste	extreme care in spending money; reluctance to spend money unnecessarily
	any of numerous sun-loving low-growing evergreens of the genus Armeria having round heads of pink or white flowers