Who is a Fabian Socialist?

Fabian Society, a socialist society founded in 1884 in London, having as its goal the establishment of a democratic socialist state in Great Britain.
The Fabians put their faith in evolutionary socialism rather than in revolution.
It's founding is attributed to Thomas Davidson, a Scottish philosopher, and its early members included George Bernard Shaw, Sidney Webb, Annie Besant, Edward Pease, and Graham Wallas.
Shaw and Webb, later joined by Webb’s wife, Beatrice, were the outstanding leaders of the society for many years.
In 1889 the society published its best-known tract, Fabian Essays in Socialism, edited by Shaw.

Source: Britannica.com