Open English Wordnet
Nouns
(n)mellownessa feeling of good humor and sympathy through maturity or intoxication or a relaxed state
(n)fullness, mellowness, richnessthe property of a sensation that is rich and pleasing“the music had a fullness that echoed through the hall”, “the cheap wine had no body, no mellowness”, “he was well aware of the richness of his own appearance”