When buying a car from the U.S. what does Clear title, no title etc mean?

 

Clear title means - There aren't any Leins on the vehicle , (The vehicle is completely paid for and without encumbrances)

No title means exactly that... The person selling the vehicle doesn't have a title to the vehicle.

This happens when a vehicle is parked and left at someone place (abandoned) and after a ONE fiscal year the property owner can keep that vehicle can sell the vehicle but they didn't have the title to it (ie: Not The Registered owner)