A donaldist is a supporter of donaldism: A fan or even researcher of Disney comics.
According to the 1977 manifest of Norwegian donaldist society "Donaldistene", "donaldists are Donald Duck fans who study Donald Duck & Co from social and political structures and viewpoints. Moreover, they try in the best possible way to preserve donaldistic cultural material for their own and others' collections."
Part of Donaldist culture is to create backronyms for names and titles; this usage stems from Carl Barks's Junior Woodchucks comics, where the scout leaders generally had long and pompous titles, leading to jocular acronyms.
The term Donaldist has been used in authorized Disney publications: the collector-themed Gemstone Publishing album series Walt Disney Treasures was advertised with the slogan/question, "Are You a Donaldist?"
Read more about this topic: Donaldism