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.
(..) and then trickled on down into some tragic Casual Corner... and then trickled on down into some tragic Casual Corner... where you, no doubt, fished it out of some clearance bin. However, that blue represents millions of dollars... and countless jobs... and it's sort of comical how you think (..)2006 The Devil Wears Prada