The deficit, less than the once unthinkable trillion dollars when Reagan took office, tripled under his management.

Still, a political development that was once unthinkable is now at least faintly possible.

What was once unthinkable - luxury housing on industrial sites - is now becoming more common across the country.

So broken ties, once unthinkable, are a real possibility now.

The effect, said one diplomat, has been to "make what was once unthinkable banal."

They point to the once unthinkable success of a white rapper like Eminem.

We've got to do things that were once unthinkable.'

In 2012 drafts, the once unthinkable just might happen.

The scene at the entrance to town today was once unthinkable.

"I think we're getting close to what was once unthinkable: the possiblity that the Fed could ease at some point," he added.