thrift vs frugalness

thrift and frugalness both are nouns.

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

As nouns, frugalness is a hypernym of thrift; that is, frugalness is a word with a broader meaning than thrift:

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

Other hypernyms of thrift include frugality.

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