candidness vs candour

candidness and candour both are nouns.

Word	Noun	Adjective	Verb	Adverb
candidness	Yes	No	No	No
candour	Yes	No	No	No

As nouns, candidness and candour are synonyms defined as:

candidness and candour: the quality of being honest and straightforward in attitude and speech

Other synonyms of candidness include candor, directness, forthrightness, frankness.

candidness (noun)	candour (noun)
the quality of being honest and straightforward in attitude and speech	the quality of being honest and straightforward in attitude and speech
	ability to make judgments free from discrimination or dishonesty