Spouse, Disinheriting
People are generally permitted to give away their property however they wish. Any person or entity may be named as a beneficiary of all or any portion of the estate.  Having this freedom means a testator is also not required to name any person or entity as a beneficiary, even a spouse.
 

However, Pennsylvania provides surviving spouses with the right to take an elective share equal to one-third of the deceased spouse's property, even when a will specifically excludes that spouse.

See: Elective Share, Generally; Elective Share, Eligibility