candour vs candidness

candour and candidness both are nouns.

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

As nouns, candour and candidness are synonyms defined as:

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

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

candour (noun)	candidness (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