- back something up
Example: Back up your car so that you can avoid the fire hydrant.
I remember my first time driving after I passed my driving exam and received my license. I was backing up my car to pull out of the driveway, and I crashed into my dad’s car! Luckily there was not much damage, just a small scratch to his driver-side mirror.
2. back someone up
Example: I trust that my family will always back me up when I need them.