Batman is extremely secretive and generally works alone, though he's rumored to have worked alongside the Gotham police department.

Klein is an extremely secretive man, and almost nothing is known about him.

All of his clerics are extremely secretive and trust only fellow cultists.

They were considered bright, but odd and extremely secretive.

If they do exist, these creatures are extremely secretive and are rarely even glimpsed.

Cope and Marsh were extremely secretive as to the source of their fossils.

Bush's style in the Oval Office was described during this period as "extremely secretive."

He was extremely secretive, far more than anyone ever realized.

They are known for being extremely secretive and well camouflaged.

The Familists were extremely secretive and wary of outsiders.