"A Gun in the House" uses a phony layer of social significance to disguise a sick and lurid thriller. The CBS film, at 9 tonight on Channel 9, recruits the "issue" of gun control as the pretext for another hard-breathing nail-biter about a terrorized housewife.

The writers -- James M. Miller and former Washingtonian Stephen Zito -- may not be guiltless, but it has to be said they probably gave the network what it wanted. Director Ivan Nagy gets the social content out of the way quickly so he can concentrate on the torture of the endangered heroine, played with her usual puffy transparency by Sally Struthers.

"Gun in the House" may have less to do with the matter of gun control, which gets a cursory glance or two in the course of the bubbly potboiling, than with what some see as the current trend in horror movies: Trap a woman alone in the house and threaten her within an inch of her life, or sometimes much closer.

On Monday, NBC offered a remake of "Midnight Lace" with Mary Crosby as, to quote that network, "the target of a mysterious would-be assassin who stalks her unmercifully." On March 4, CBS presents "No Place to Hide" with Mariette Hartley as "a young woman who, for unknown reasons, is stalked by a mysterious man who threatens to kill her."

Though not as graphically violent as their silver-screen counterparts, these films tend to fit into the he-knows-you're-alone, don't-answer-the-phone, he's-coming-to-get-you class. It scares some people because, although there's nothing new about endangered heroines, these films tend to dwell on torture for its own sake, and because the audience may identify more with the killer than the victim.

In tonight's film, Struthers plays the wife of an airline pilot who lives in an enormous, vulnerable house with her young daughter. She buys a gun and takes lessons in using it out of concern over the neighborhood crime wave. In one of the more pungent nonhysterical scenes in the picture, the instructor fires at a can of tomato juice with a handgun; it splatters huge red blobs against a wall when hit.

"I don't think I could do that to another person, Emily," the Struthers character says to a friend.

But the film has opened with a relatively explicit rape scene -- the wife of another pilot being told by one of her two assailants, "You're really gonna like this." She is thrown to the floor and her clothes are torn. The scene ends with a shot of one partner preparing to unfasten his belt. Later, in the getaway truck, the older tells the younger, "You did okay . . . for an almost-virgin."

This is a tease for the big attack on Struthers, an agonized and prolonged ordeal in which she is forced to kneel down on the kitchen floor while wine is poured over her head. "Wipe it up. Wipe it up with your body," the taller and more perverse of the intruders tells her.

Eventually she wrestles herself free, gets up the stairs and grabs the gun that has been stashed under the mattress. She holds the intruders at bay for a while and then, preposterously, while making an escape, the two of them stop for a chat in the kitchen. The younger and more reluctant partner is pushed back through the kitchen doors into the dining room and Struthers shoots him dead.

Then the movie turns into a perfunctory detective story in which the husband and wife try to convince skeptical police that there was another man involved and that the wife did not simply murder the kid. To add to the preposterousness, the wife is left at home alone again, the intruder returns, and she subdues him first with a baseball bat and then by tackling him and pummeling him with her fists -- a feeble blast of feminism when compared with the many minutes of woman-torture that precede it.

Perhaps if the film didn't hide behind a pose of social relevance, the thriller contrivances wouldn't seem so outrageous (the intruder, seemingly unconscious, springs up suddenly at the heroine, as in "Wait Until Dark"). But "Gun in the House" is worse than just another piece of rank exploitation. It's a liar and a cheat as well.