patsy

from WordNet (r) 3.0 (2006)

patsy
    n 1: a person who is gullible and easy to take advantage of
         [syn: {chump}, {fool}, {gull}, {mark}, {patsy}, {fall guy},
         {sucker}, {soft touch}, {mug}]

from Moby Thesaurus II by Grady Ward, 1.0

38 Moby Thesaurus words for "patsy":
      babe, boob, chump, cinch, credulous person, cull, dupe, easy mark,
      easy pickings, fall guy, fish, fool, goat, gobe-mouches, greener,
      greenhorn, greeny, gudgeon, gull, innocent, leadpipe cinch, mark,
      monkey, pigeon, plaything, prize sap, pushover, sap, saphead,
      scapegoat, schlemiel, sitting duck, stooge, sucker, toy,
      trusting soul, victim, whipping boy