WordNet (r) 3.0 (2006):

pinko
    n 1: a person with mildly leftist political views [syn: pinko,
         pink]

Moby Thesaurus II by Grady Ward, 1.0:

24 Moby Thesaurus words for "pinko":
   Bolshevik, Jacobin, Wobbly, anarchist, anarcho-syndicalist,
   extreme left-winger, extremist, left-wing extremist,
   lunatic fringe, mild radical, nihilist, parlor Bolshevik,
   parlor pink, pink, radical, red, revolutionary, revolutionist,
   sans-culotte, subversive, syndicalist, ultra, ultraist, yippie