back-ender
A car accident in which one car hits the back of the car in front of it. I heard that a lot of people had back-enders during that snowstorm last week.
rear-ender
A minor car accident in which minimal damage is incurred, especially to the front and rear bumpers of the two cars involved. Michelle was a new driver so she was extremely upset when she had her first accident. Luckily, it was just a rear-ender, so there was no real damage to either car involved. I know a mechanic who specializes in providing affordable repairs for scrapes, scratches, and rear-enders. You need to start slowing down much sooner when you're coming up to a red light, or sooner or later you'll end up causing a rear-ender with the car ahead of you.