In Florida, probate is a court proceeding which administers a deceased person's estate. It may be done either testate--with a Will--or intestate--without a Will. The probate process is usually referred to as "administration" of the estate.
However, in addition to the administration of an estate, sometimes disputes arise in probate. The court process of fighting over these disputes is what we sometimes call "estate litigation" or "probate litigation." Effectively, this is analogous to a lawsuit within the probate proceeding. In fact, in most probate litigation cases, the challenging party will declare that the action is "adversary" and thereby trigger certain rules of procedure involving the dispute.
One of the most common disputes leading to probate litigation involves challenging a person's Last Will and Testament. Will challenges, or Will contests as they are sometimes called, are most often based on undue influence, fraud or duress. For example, if three weeks before a person's death, he or she makes a new Will excluding his or her children and leaving everything to a caretaker, the children might challenge the Will as a result of undue influence by the caretaker.
Will contests also sometimes involve challenges to the person's competence at the time they executed a Will. For example, in the above example, if the person naming the caretaker was suffering from dementia or some other debilitating illness at the time they execute a new Will, that person might not have been competent and the Will may thereby be subject to challenge. The litigation would bring the matter before the probate court to be decided.
In addition to Will contests, probate litigation sometimes involves other disputes over how an estate is being handled. One common dispute arises where there's a dispute over who will be appointed as Personal Representative of the estate. Another common disputes arises when a Personal Representative--the person appointed by the court to administer the estate--fails to include all estate assets in the estate Inventory. Some beneficiaries may challenge the Inventory as not being accurate, thereby resulting in the court ordering a more complete Inventory.
In any probate litigation, the party mounting the challenge needs to be represented by experienced probate counsel--and preferably one who has litigation (court room) experience.