Optimism is the feeling of being hopeful about the future or about the success of something in particular. The Indian Prime Minister has expressed optimism about India's future relations with the USA. a mood of cautious optimism. pessimism. a tendency to believe that good things will always happen pessimism grounds/cause/reason for optimism (optimisme, from optimum; OPTIMUM)
The opinion or doctrine that everything in nature, being the work of God, is ordered for the best, or that the ordering of things in the universe is such as to produce the highest good