But it was widely seen as the ultimate act of treachery.

For example, we might define the ultimate hostile act as the taking of life.

Is it because it's supposed to be the ultimate act of great passion?

Yet it would also be the ultimate act of selfishness.

Rebuilding would be the ultimate act of defiance against terrorism.

It simply makes no sense and would be the ultimate act of turning the war into a crime.

She liked that above all things except the ultimate act.

Knowing he was capable of the ultimate brutal act, would she ever be at ease with him again?

This is the ultimate act of war against us.

To many people, he said, it would have seemed like an ultimate act of unilateralism.