a volcano that is not likely to erupt again
volcano which is not currently erupting and which isn't likely to do so in the future.
a volcano that is never expected to erupt again.
A volcano that is not presently erupting and is not likely to do so for a very long time in the future. Usage of extinct.
A volcano that is not expected to erupt again.
volcanoes no longer liable to erupt
A volcano that shows no signs of ever erupting again.