What is uninsured motorist?

Coverage that protects you and the people in your car in the event another driver hits you with inadequate insurance coverage or no insurance at all.  Often drivers that carry low auto insurance limits do not have many assets to protect.  So in the event that you or someone in your car is badly injured by another driver and they have inadequate auto insurance liability limits there is nothing to gain by suing the driver.
In that case you can put a claim in under your own insurance policy.
Uninsured Motorist/Underinsured Motorist is an inexpensive coverage that is extremely important.