term:

Disherison

disherison n

[Anglo-French dishereison desheriteson, from Old French deseriteison, from desheriter to disinherit, from des-, prefix marking reversal + heriter to inherit, from Late Latin hereditare]
: the act of disinheriting

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.