Here are some examples:
* "Whizzpopping": Used in "Charlie and the Chocolate Factory" to describe the sound of a chocolate river.
* "Oompa Loompas": A made-up name for the small, orange workers in his factory.
* "Bouncing": Used in "Matilda" to describe the act of reading books so excitedly that one jumps up and down.
While these aren't new words, Dahl's use of language and his unique phrasing contributed to his distinctive and memorable writing style.