A Pollyanna is a blindly or foolishly optimistic person. The term derives from Eleanor H. Porter’s 1913 novel, Pollyanna, about an orphan with an unjustifiably optimistic attitude. The word is primarily an Americanism. It is rare in British and Canadian English, but it appears relatively often in Australian and New Zealand English.
The word is spelled like the book title, and it is capitalized. The adjective, Pollyannaish (not Pollyanna-ish—no hyphen needed), meaning foolishly optimistic, is likewise usually capitalized. And though Pollyannaish is the prevailing adjective, Pollyannish appears about a third of the time. The latter will likely continue to gain ground because it’s easier to pronounce. Meanwhile, if Pollyanna and its derivatives survive in the language, they’ll probably lose the capital.
Some writers give Pollyanna an indefinite article (e.g., I hate to be a Pollyanna), and others omit the article (e.g., I hate to be Pollyanna).
The public is much more likely support enforcement efforts than the political class, which is dominated by open-borders Pollyannas on both sides of the aisle. [New York Times]
Given the sheer quantity of junk to be seen, such a declaration seems absurdly Pollyannaish. [Newsweek]
If the Pollyanna thinking doesn’t work, Weiner could also try emigrating to France. [The Canberra Times]