The documents are only available to people with 'security clearance' [=special permission given only to people who are approved to know or see secret things] from the government.
The car has a 'road/ground clearance' of seven inches. [=the bottom of the car is seven inches above the road/ground]
You'll have to get 'clearance' [='approval'] from management to go ahead with the project.
(..) Ended up supercharging our Wi-Fi. Wish he could do that at our residence. I got security clearance. Maybe later this week I'll come by. Gentlemen, we should be good here. Call you later to check in. (..)2016 13 Hours