Incoercible /(?)/

In·co·er·ci·ble

Incoercible

a.
  1. Not to be coerced; incapable of being compelled or forced.
  2. Not capable of being reduced to the form of a liquid by pressure; -- said of any gas above its critical temperature. (Physics)
  3. That can note be confined in, or excluded from, vessels, like ordinary fluids, gases, etc.; -- said of the imponderable fluids, heat, light, electricity, etc. (Physics)