|leading light (ˈliːdɪŋ)|
|1.||an important or outstanding person, esp in an organization or cause|
|2.||nautical a less common term for range light|
An important or influential individual, as in Jim was a leading light in his community. This expression, alluding to moral guidance, dates from about 1870, but terms such as a shining light have been used for an outstanding person since the first half of the 1500s.