Entry: jounce (v.)
In context: "...the excessive speed of the northbound bus made it jounce godawfully..."
Definition: intr. To move violently up and down, to fall heavily against something; to bump, bounce, jolt; to go along with a heavy jolting pace.
Other: This is sort of a neat subscript to the entry:
Etymology: Of obscure origin: it has been compared to jaunce v., which it partly approaches in use, but with which it can scarcely be phonetically connected. Several words in -ounce, as bounce, flounce, pounce, trounce, are of obscure history.
SNOOT score: 1
Source: Oxford English Dictionary