The Collaborative International Dictionary
Incoercible \In`co*er"ci*ble\, a. [Pref. in- not + coercible: cf. F. incoercible.]
Not to be coerced; incapable of being compelled or forced.
(Physics) Not capable of being reduced to the form of a liquid by pressure; -- said of any gas above its critical temperature.
(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.
Wiktionary
a. 1 Not to be coerced; incapable of being compelled or forced. 2 (context physics of a gas English) Not capable of being reduced to liquid form by pressure. 3 (context physics archaic English) That cannot be confined in, or excluded from, vessels, like ordinary fluids, gases, etc.; said of heat, light, electricity, etc.