If Roald Dahl lived on today, the author would be 100 years old on Tuesday. It is an occasion to miss the macabre word magician who brought us characters like Willy Wonka, Matilda, the fantastic Mr. Fox and James (he of the giant peach). And it’s also an occasion to celebrate an irreverent, playful mind that created not only fascinating creatures and people but fascinating words to put in their mouths.
To coincide with the centennial, the editors at Oxford University Press are publishing not just a collection but a dictionary of words in Dahl’s works, with a special focus on the “extra-usual” ones he made up. Take TIME’s quiz, based on the Oxford Roald Dahl Dictionary, to see just how scrumdiddlyumptious your vocabulary is.