There are not many antonyms for the word "factiousnesses" as it is a rather uncommon and complex term. However, we can understand its meaning by breaking it down. "Factiousness" means the tendency to cause dissension or division, while "-nesses" is a plural suffix that expresses a quality or state of being. So, the antonyms for factiousnesses could be terms that denote unity, agreement or harmony, like cooperation, consensus, concord, solidarity or unanimity. In contrast, antonyms for "factiousnesses" could also include words that imply non-involvement or neutrality, like impartiality, detachment, neutrality, or objectivity.