There are several synonyms for the word "picketer" that are commonly used. One such synonym is "demonstrator," which refers to someone who participates in a public display or protest to express their views. Another synonym is "protester," which describes someone who objects to something, often by participating in a public display of dissent. Other synonyms for "picketer" include "striker," which refers to someone involved in a labor strike or work stoppage, and "marcher," which describes someone who takes part in a march or demonstration. Additionally, the term "activist" can be used to describe individuals who engage in various forms of political or social activism, including picketing as a form of protest.