Walter Mitty:
https://en.wikipedia.org/wiki/Walter_MittyMitty is a hapless, absent-minded man with a vivid fantasy life. His apparent incompetence and inattention result in him being criticized, mocked, and otherwise treated dismissively. At the same time, Mitty's surroundings trigger him to enter fantasies in which he occupies a radically different social position, where he is assertive and authoritative, exceptionally competent, or formidable.
Mitty is a meek, mild-mannered man with a vivid fantasy life. In a few dozen paragraphs, he imagines himself a wartime pilot, an emergency-room surgeon, and a devil-may-care killer. Although the story has humorous elements, there is a darker and more significant message underlying the text, leading to a more tragic interpretation of the Mitty character. Even in his heroic daydreams, Mitty does not triumph, several fantasies being interrupted before the final one sees Mitty dying bravely in front of a firing squad. In the brief snatches of reality that punctuate Mitty's fantasies, the reader meets well-meaning but insensitive strangers who inadvertently rob Mitty of some of his remaining dignity.
Popular culture
The character's name has come into more general use to refer to an ineffectual dreamer and appears in several dictionaries. The American Heritage Dictionary defines a Walter Mitty as "an ordinary,
often ineffectual person who indulges in fantastic daydreams of personal triumphs".