The phrase "leading light" refers to a prominent or influential member in a group or an industry. Some synonyms for this term include "pillar," "keystone," "vanguard," "trailblazer," and "trendsetter." A pillar is someone who is relied upon for support and guidance, while a keystone is an essential component that holds everything together. The term vanguard is used to describe someone who is at the forefront of a movement or trend, while a trailblazer is someone who is pioneering a new path. Finally, a trendsetter is an individual who has the power to shape and influence the direction of popular culture. Each of these synonyms highlights the importance and impact of a leading light in their respective field.