Multiple realities
(covers information from several alternate timelines)
A figurehead was a ruler who had little power but symbolic value.
According to mirror Voq, that universe's Michael Burnham gave the "[...] single savage order you executed thousands of my kind, establishing [her]self as the figurehead of Terran cruelty." (DIS: "The Wolf Inside")
In 2369, Worf suggested that although the clone of Kahless would be a figurehead, his presence as Emperor of the Klingon Empire would go a long way towards returning honor to the Klingon people. (TNG: "Rightful Heir")
After the fact, in 2372, Kor called this clone a "toothless figurehead", saying that the Sword of Kahless would only be able to unite the Klingon people if held by a warrior like Kang and Koloth. (DS9: "The Sword of Kahless")