from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A passenger who constantly advises, corrects, or nags the driver of a motor vehicle.
- n. A person who persists in giving unsolicited advice.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A person sitting in the back-seat of a car issuing (unsolicited and usually unwanted) instructions to the driver.
- n. An opinionated person who offers (unsolicited and often unwanted) advice on the best way to handle a situation.
Sorry, no etymologies found.