good humour vs good humor

good humour and good humor both are nouns.

Word	Noun	Adjective	Verb	Adverb
good humour	Yes	No	No	No
good humor	Yes	No	No	No

As nouns, good humour and good humor are synonyms defined as:

Other synonyms of good humour include amiability, good temper.

good humour (noun)	good humor (noun)
a cheerful and agreeable mood	a cheerful and agreeable mood