The Collaborative International Dictionary
Incremable
Incremable \In*crem"a*ble\, a. [Pref. in- not + L. cremabilis
combustible, fr. cremare to burn.]
Incapable of being burnt; incombustibe.
--Sir T. Browne.
Wiktionary
incremable
a. (context obsolete rare English) incombustible; resistant to being burnt.