An underground filmmaker refers to the work of directors who "played an anti-art role in Hollywood"
Check this source for more details: http://en.wikipedia.org/wiki/Underground_film
Underground Filmmaker can also refer to a director/producer who might be making a movie under an anonymous name #1 because society/government rejects its content, or #2 because there is unauthorized copyright material used. Mainly done to avoid percussion by individuals, companies, or the government, while attempting to get a movie to public view.
Ken Anderson - filmmaker - died in 2006.
Ross McLaren - filmmaker - was born in 1953.
Stuart Walker - filmmaker - died in 1941.
Stuart Walker - filmmaker - was born in 1888.
Keith Beauchamp - filmmaker - was born in 1972.
António Ferreira - filmmaker - was born in 1970.
Robert Banks - filmmaker - was born in 1966.
Terry Moloney - filmmaker - was born in 1969.
Devi Sharma - filmmaker - died in 2010.
John O'Brien - filmmaker - was born in 1962.
Roger Christian - filmmaker - was born in 1944.
Anthony Rizzo - filmmaker - was born in 1918.