(3) For "double agent," Maltz liked the slang expression jey'naS ghoqwI'  (literally, "double-headed ax spy").  He said the non-slang term 'o'wen could also be used for "double agent," but its meaning is a bit broader -- it's used to refer to someone (or something) of ambiguous status.  As Maltz put it, "You're not quite sure if it's this or that. You think it's one thing, and it may be, but it may be another."