Source : Webster's Revised Unabridged Dictionary (1913)

Incoercible \In`co*er"ci*ble\, a. [Pref. in- not + coercible:
   cf. F. incoercible.]
   1. Not to be coerced; incapable of being compelled or forced.

   2. (Physics) Not capable of being reduced to the form of a
      liquid by pressure; -- said of any gas above its critical
      point; -- also particularly of oxygen, hydrogen, nitrogen,
      and carbon monoxide, formerly regarded as incapable of
      liquefaction at any temperature or pressure.

   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.