infrangible adjective. 
[ɪn'frandʒɪb(ǝ)l] L16.[French, or medieval Latin infrangibilis, formed as IN-3 + frangibilis FRANGIBLE.]1.  Unbreakable. 
L16.■ F. W. Robertson No iron bar is absolutely infrangible. fig.: 
■ J. Updike That heaping measure of maternal love which makes for an infrangible soundness of spirit.2.  Unable to be infringed; inviolable. 
M19. ■   infrangi'bility noun E19. ■   infrangibly adverb E19.  [TahlilGaran] English Dictionary ▲