In politics, a figurehead is a person who holds de jure (in name or by law) an important title or office (often supremely powerful), yet de facto (in reality) executes little actual power. The metaphor derives from the carved figurehead at the prow of a sailing ship. Commonly cited figureheads include Queen Elizabeth II, who's Queen of sixteen Commonwealth realms and head of the Commonwealth, but has no power over the nations in which she isn't head of state and doesn't exercise power in her own realms on her own initiative. Other figureheads are the Emperor of Japan, the King of Sweden, or presidents in majority of parliamentary republics, such as the President of India, President of Israel, President of Bangladesh, President of Greece, President of Germany, President of Pakistan (starting in 2010), and President of China (without CPC General Secretary and Chairman of CMC posts).
During the crisis of the March on Rome in 1922, King Victor Emmanuel III of Italy, though a figurehead, played a key role in handing power to Benito Mussolini. More than 20 years later, the same King Victor Emmanuel III of Italy played a key role in the dismissal of Benito Mussolini in 1943. Since the abolition of monarchy in Italy and the establishment of a republic in 1946, the Italian President assumed most of the ceremonial functions of the previous kings; however, the Italian President retains large powers in appointing a prime minister of his choice when in parliament there's no clear majority government, creating a so-called "president's cabinet" (a technocratic cabinet). For example, the former Prime Minister of Italy, Sen Mario Monti, was appointed by the Italian President Giorgio Napolitano as a lifetime-senator and then as Prime Minister of the country, not after a new election. Italian President's powers and influence are so much stronger is the weaker political parties' leadership. This system is called "accordion ".
Conversely, King Juan Carlos I of Spain, additionally largely considered a figurehead, had in 1981 a key role in defending the newborn Spanish democracy and foiling the attempted coup d'état, known as "23-F".
As a derogatory term
The word can additionally have more sinister overtones, and refer to a powerful leader, who should be exercising full authority, who's actually being controlled by a more powerful figure behind the throne.