Learn how to say Optimists correctly in English with this tutorial pronunciation video.
Oxford dictionary definition of the word optimism:
1hopefulness and confidence about the future or the success of something:
the talks had been amicable and there were grounds for optimism
2 Philosophy the doctrine, especially as set forth by Leibniz, that this world is the best of all possible worlds.
the belief that good must ultimately prevail over evil in the universe.
mid 18th century: from French optimisme, from Latin optimum ‘best thing’ (see optimum)