Thanks to their astute reading, Harry Potter fans will at least know what is meant if they get accused of lounging around insolently, haphazardly or malevolently as they wait for the latest title, The Half Blood Prince, to hit bookshops in 16 days.

For anyone else who is baffled, passages throwing light on these words and many others appear today in the first children's dictionary to include citations from the best of children's literature.

"Insolent, adjective - very rude and insulting," says the Oxford Primary Dictionary. Then it quotes from The Prisoner of Azkaban: "Malfoy gave Professor Lupin an insolent stare, which took in the patches on his robes and the dilapidated suitcase."

"Haphazardly" is explained by a quote from The Chamber of Secrets: "Mrs Weasley was clattering around, cooking breakfast a little haphazardly, throwing dirty looks at her sons as she threw sausages into the frying pan."

And Professor Snape makes "malevolent" easy: "'A bad idea, Professor Lockhart,' said Snape, gliding over like a large and malevolent bat."

Dr Samuel Johnson pioneered the use of citations in adult lexicography in 1755 with his first English dictionary. Citations in the Oxford Primary Dictionary range from the Victorian author Charles Kingsley in Westward Ho! ("A thousand birds burst into jubilant song," 1855) to Philip Pullman's use of "brigand" in his new story The Scarecrow and His Servant: "The chief brigand was a ferocious looking man, with two belts full of bullets crisscross over his shoulders."

The Oxford Primary's editors say good authors "provide wonderful citations for dictionary definitions because the language and vocabulary they employ is straightforward, descriptive and helps children to understand meaning and context right away."

They add that their "choice of citations from texts children are intimately familiar with sets a fantastic example for children and helps improve their reading and writing skills".