Two new movies opened Friday, both excellent adult dramas of the kind we get all too rarely these days, "Guilty By Suspicion" and "Class Action." And though they are completely different in their subject matter, they do have something in common - something that points up just how arbitrary and inconsistent the movie rating system is.

"Guilty By Suspicion" is an examination of the House Un-American Activities Committee witch hunt in the 1950s, with Robert De Niro as a movie director who finds himself on the Hollywood blacklist."Class Action" is a father-daughter reconciliation drama set against a courtroom backdrop, starring Gene Hackman and Mary Elizabeth Mastrantonio. (Interestingly, "Class Action" mentions the McCarthy hearings in a speech by Hackman's character about how he met his wife.)

What the two films have in common is that both are relatively free of the kind of offensive excesses we so often see in movies today. Neither film has any violence, there is no simulated sex in either film, no nudity and no drug abuse.

Both films do have profanity, however, including the one cuss word - the Eddie Murphy Word, if you will - that is considered to be more offensive than any other by the Classification and Ratings Administration, which operates under the scrutiny of the Motion Picture Association of America.

Now here's the irony: "Guilty By Suspicion" uses the word probably three times as much as "Class Action." Yet "Guilty By Suspicion" is rated PG-13 while "Class Action" is rated R.

Unfortunately, some moviegoers will stay away from "Class Action" because of its R rating but will feel fine about attending "Guilty By Suspicion" because it is merely rated PG-13. (And that's true, by the way, of certain moviegoers all over the country, not just in this Mormon-dominated market.)

This brings to mind a number of other R-rated movies released over the years, which are so rated for no reason other than the use of the Eddie Murphy Word a few times - "Ordinary People," "The Verdict," "The Milagro Beanfield War," etc. And if memory serves, none of these movies use the profanity any more - and maybe less - than "Guilty By Suspicion."

None of this is meant to indict "Guilty By Suspicion," which is a fine film and which, in its use of the word in question, doesn't come close to movies like "Beverly Hills Cop" or "Die Hard." In "Guilty By Suspicion" the profanity is used logically and in angry, frustrated moments - not as just another benign word in the vocabulary.

But the fact remains that it is used a heck of a lot more in that film than in "Class Action," which nonetheless is branded with an R, considered by some audiences the modern-day equivalent of Hester Prynne's "A."

Of course, discriminating audiences know there are many inconsistencies in the rating system - ranging from such disparate films as "Awakenings" (quite clean, save a couple of profanities, including the Eddie Murphy Word spoken once) and "Dances With Wolves" (replete with violence, sex and nudity) carrying the same rating, PG-13; to "King Ralph" (a very raunchy scene in a strip joint, as well as vulgar and profane language) and "Teenage Mutant Ninja Turtles II" (comic violence only) carrying the same rating, PG.

Not to mention that by virtue of its rating, "Class Action" is categorized with such push-the-R-to-the-limit films as "The Silence of the Lambs" and "The Doors."

No wonder parents are confused.

They are not half as confused, however, as the members of the rating board.