The hardboiled private eye is not quite noir enough for the more cynical critics, who like their noir Jim Thompson style, or blacker than black. The idea of having some Shopworn Galahad walking down the mean streets of Noir City strikes this type of critic as rank idealism if not moronic optimism. For this kind of critic, the defining noir protagonist is the grifter, the weasel and con artist who tries to worm his way to the top by hook or by crook.
The classic example of the grifter character is Harry Fabian from “Night and the City,” a two-bit hustler from America trying to slime his way into control of the London wrestling business. Harry has the entirely undeserved love of a good woman, but that's not enough to save him from his own cleverness as he tries to play one set of underworld characters against the other in hopes of getting rich as quickly as possible. As one of the other characters says to him, “You've done a sharp thing, Mr. Fabian. Maybe sharp enough to cut your throat.”
This being an earlier era, Harry must eventually pay for his amoral ways, despite which the movie was seen as trashy and amoral at time, merely for having him as its protagonist. In the “extreme noir” books of Jim Thompson, grifters and other sociopaths are never punished for their actions- they are merely destroyed by other grifters and sociopaths, who seem to be practically the only inhabitants of Thompson's relentlessly unpleasant world.
