unsustainable

The university added all but four of its modern language courses had fewer than 10 students on them and they were currently "unsustainable".

"The current pretence is unsustainable, and seems to put all the burden and blame on the victims," he told the BBC.

However, there were some of us who knew the method was unsustainable.

But here’s a possible constructive scenario: In a few months there will be a new Fed chair who will probably attempt to grow the U.S. out of these unsustainable fiscal deficits.

Yet the OBR says the purpose of its long-term projection is to highlight that the UK's public finances are currently on what it calls an "unsustainable" trajectory.