asceticism vs austerity

asceticism and austerity both are nouns.

Word	Noun	Adjective	Verb	Adverb
asceticism	Yes	No	No	No
austerity	Yes	No	No	No

As nouns, asceticism and austerity are synonyms defined as:

asceticism and austerity: the trait of great self-denial (especially refraining from worldly pleasures)

Other synonyms of asceticism include nonindulgence.

asceticism (noun)	austerity (noun)
rigorous self-denial and active self-restraint	the trait of great self-denial (especially refraining from worldly pleasures)
the trait of great self-denial (especially refraining from worldly pleasures)
the doctrine that through renunciation of worldly pleasures it is possible to achieve a high spiritual or intellectual state