Definition of "undergrounder"

undergrounder

/ˌʌn.dəˈɡɹaʊn.də/

noun
plural undergrounders
1. An underground publication or movie.
  Quotations
  The excess that is so noticeable in Stevens's brawl is absent in the least serious undergrounder, […]
  1957, Manny Farber, "Underground Films", in Robert Walsh (ed.) Negative Space: Manny Farber on the movies (1998), p. 27
  Street people, day-trippers, and tourists pushed the paper's circulation to 117,000, the largest any community undergrounder would reach.
  1985, Abe Peck, Uncovering the Sixties: The Life and Times of the Underground Press, p. 51
2. A person who dwells underground.
  Quotations
  […] sewer people, derelicts, bag ladies, undergrounders, and Bowery bums. Whatever the cause of their illness, as in Scanners, homeless people are victims but, more importantly, a threat to be eliminated.
  2017, Stephen Pimpare, Ghettos, Tramps, and Welfare Queens, page 227
3. One who is part of a secret or underground society or subculture.
  Quotations
  His tactics appealed to the type of Old Bolshevik undergrounder who had little patience with theoretical hairsplitting and who looked to a firm authority to take the lead in practical work.
  1985, Robert Vincent Daniels, chapter 7, in Russia: The Roots of Confrontation, page 167