Hi there,
As a general rule, legal heirs are entitled to a compulsory share of an estate - as laid out in the moneyland.ch guide to Swiss inheritance laws.
However, a person can - under extraordinary conditions - have the compulsory share of an inheritance waived.
A person may disinherit a legal heir under these circumstances:
1. The legal heir commited a legally substantiated crime which directly affected them personally.
2. The legal heir has debts which result in total losses for lenders. In this case, the person may withold 50% of the compulsory share of the legal heir's inheritance and bequeath it directly to the legal heir's children. This is only an option if the legal heir has children.
3. The legal heir grossly fails in their legal obligations to their family. This primarily applies to possible legal obligations to support relatives financially.
While it would be very difficult to deny you your compulsory share of an inheritance, your parent could easily deny you the non-compulsory share by writing a will and leaving that portion of their assets to another beneficiary.
Best regards from Moneyguru
More on this topic:
Inheritance tax explained