Amiability : the quality of having a friendly and pleasant manner; geniality.Pessimism : a tendency to see the worst aspect of things or believe that the worst will happen.Prudence : the quality of being prudent; cautiousness.Sincerity : the absence of pretence, deceit, or hypocrisy.Petulance : the quality of being childishly sulky or bad-tempered.Antonym of Amiability is Petulance