rigourousness vs rigorousness

rigourousness and rigorousness both are nouns.

Word	Noun	Adjective	Verb	Adverb
rigourousness	Yes	No	No	No
rigorousness	Yes	No	No	No

As nouns, rigourousness and rigorousness are synonyms defined as:

Other synonyms of rigourousness include asperity, grimness, hardship, rigor, rigour, severeness, severity.

As nouns, rigourousness and rigorousness are synonyms defined as:

Other synonyms of rigourousness include hardness, harshness, inclemency, rigor, rigour, severeness, severity, stiffness.

rigourousness (noun)	rigorousness (noun)
something hard to endure	something hard to endure
excessive sternness	excessive sternness