From Longman Dictionary of Contemporary Englishoptimistop‧ti‧mist /ˈɒptəmɪst $ ˈɑːp-/ noun [countable] EXPECTsomeone who believes that good things will happen OPP pessimist He’s an eternal optimist (=he always believes that good things will happen).
Examples from the Corpus
optimist• Optimists still believe we can resolve the problem without going to war.• You have to be an optimist to be in an occupation such as farming.• His trouble, Hicks thought, was that he was too much of an optimist, like all hustlers.• Most entrepreneurs tend to be optimists.• He had clean-cut, perfect features, an absolutely even gaze, and the erect, confident air of a nineteenth-century optimist.• Diehard optimists, like Mr Pynzenyk, say that hyperinflation and economic collapse will eventually force the country to its senses.• He is extremely serious, speaks slowly-almost grinding to a complete halt at times-and is not exactly the happy optimist.• But Stirling, the incurable optimist, was already making new plans.• The perennial optimists would say that this is because of consumer demand.From Longman Business Dictionaryoptimistop‧ti‧mist /ˈɒptəmɪstˈɑːp-/ noun [countable] someone who believes things will get better or be more successful in the futureAs major companies in this sector continue to show poor results, even optimists are getting worried. → compare pessimist —optimistic adjectiveHe remains optimistic about the company’s long-term prospects.The government’sover-optimistic economic forecasts have encouraged manufacturers to put too many products into their inventories. 