A filibusterer is someone who obstructs a legislative process, often by making long speeches or engaging in other obstructive tactics. There are several synonyms that can be used to describe such a person. One such term is obstructionist, which refers to someone who intentionally blocks or interferes with progress. Another synonym is stonewaller, which refers to someone who refuses to answer questions or provide information in order to obstruct a process. Finally, the term delay tactic or delaying tactic can also be used to describe a filibusterer, indicating that their actions are intended to slow down or delay legislative progress.