Disherison

from The Collaborative International Dictionary of English v.0.48

disherison \dis*her"i*son\ (d[i^]s*h[e^]r"[i^]z'n), n. [See
   {Disherit}.]
   The act of disheriting, or debarring from inheritance;
   disinherison. --Bp. Hall.
   [1913 Webster]

from Bouvier's Law Dictionary, Revised 6th Ed (1856)

DISHERISON. Disinheritance; depriving one of an inheritance. Obsolete. Vide 
Disinherison.