incoercible

a. [ Pref. in- not + coercible: cf. F. incoercible. ] [ 1913 Webster ]

1. Not to be coerced; incapable of being compelled or forced. [ 1913 Webster ]

2. (Physics) Not capable of being reduced to the form of a liquid by pressure; -- said of any gas above its critical temperature. [ 1913 Webster +PJC ]

3. (Physics) That can note be confined in, or excluded from, vessels, like ordinary fluids, gases, etc.; -- said of the imponderable fluids, heat, light, electricity, etc. [ 1913 Webster ]