This is going to be a simple game, but not so simply done. People going to or from another language often stumble to find a word. Sometimes for a word that does not really exist for a specific idea they want to communicate. Language is the verbalization of a feeling, impression or idea. In that theme, create a new word, using base roots to describe the feeling you get when ride in a car over a really good fun bump. Better yet, create two words, one based on root word and another less serious that expresses the feeling.