A "square" is an "ichabod" (someone who is icky), a "stoopnagle", a "rube", a "dumb-bunny", in African-American talk, an "ofay" which is probably related to oaf, a "peckerwood" (again African-American, a "hick", a "lamebrain", a "mark" (easilly taken advantage of), "fair game" (Aussie or Scientology), "out of the loop", ....these for starters

Frank