Stoppard's 'Real Thing' is witty - and warmly human

The Real Thing. Comedy by Tom Stoppard. Starring Jeremy Irons, Glenn Close. Directed by Mike Nichols.

The real thing at the heart of the new Tom Stoppard import at the Plymouth Theatre is the survival of a loving relationship amid the threats that imperil it. Since ''The Real Thing'' is a Stoppard play, matters are not as plain and simple as all that. The course of true love runs anything but smooth in this quirky and literate offering by Britain's wittiest contemporary playwright.

''The Real Thing'' deals with various subjects on several levels in Mr. Stoppard's version of romantic comedy. If the verbal fireworks are less spectacular than in earlier Stoppard plays, there is perhaps more human fire, or at least warm human feeling.

The opening scene turns out to be the nonreal thing - a fragment from a play entitled ''House of Cards,'' in which Charlotte and Max appear to be breaking up their marriage. The two characters retain their first-scene names throughout the remainder of the action. It is not long before playwright Henry (who is married to Charlotte) and actress Annie (the wife of Max) have revealed their love for each other and separated from their respective mates. The new relationship becomes the central concern of ''The Real Thing.''

The test of Henry's devotion to Annie occurs when she prevails on her literately fastidious husband to revise the clumsy script by a loutish pacifist named Brodie, who has been jailed for desecrating the London Cenotaph and whose cause Annie has espoused. The telecast of Henry's version brings Brodie's release, but the young activist sneers at the bourgeois doctoring. For Brodie, it is not ''the real thing.'' On the other hand, Henry's loving gesture reclaims the briefly unfaithful Annie.

The denouement seems more mechanical than plausible - in part because Mr. Stoppard has made Brodie such a setup for Henry, and in part because Annie's commitment, even for an impulsive naif, strains credibility. Such reservations apart, ''The Real Thing'' is a brilliantly comic study of manners and mores, sharply satiric about the current casual attitudes toward fidelity and infidelity, and above all filled with Stoppard's abiding exhilaration over words and images. The play is also sprinkled with snippets from and allusions to dramatists past and present: Sartre, Ford, Ibsen, Strindberg, Shakespeare, and so on, with even a sly aside to Noel Coward. Musically, the references run from opera to rock, including Bach a la Procul Harum.

Jeremy Irons's Henry seems steeped in Stoppard wit and eloquence. Mr. Irons is equally at home with Henry's meticulous verbal niceties as with his fervent defense of language as instrument of thought. He can also respond to the romantic Henry's distinction between marriage as a commitment and marriage as a bargain. Like the play itself, the Irons performance is one of the treasures of the season. And so is Mike Nichols's impeccable direction.

Miss Close brings to the offbeat role of Annie a charm and intelligence that can be very winning. Kenneth Welsh and Christine Baranski respectively fulfill the requirements of Max and Charlotte, whether as the make-believe couple of Henry's play, ''House of Cards,'' or the Pirandellian replicates of ''The Real Thing.'' There are also admirable performances by Peter Gallagher as the young fellow actor with whom Annie becomes momentarily smitten, Vyto Ruginis as the obnoxious Brodie, and Cynthia Nixon as Charlotte and Max's precociously liberated teen-age daughter.

The handsome production designed by Tony Walton moves miraculously among the London and other locales of the story (including a couple of train compartments). Anthea Sylbert has designed costumes a la mode, and the sets are beautifully lighted by Tharon Musser.

Full Hookup. Play by Conrad Bishop and Elizabeth Fuller. Directed by Marshall W. Mason.

''Full Hookup'' came to Off Broadway's Circle Repertory Company with its credentials and auspices well in order. It was written by Conrad Bishop and Elizabeth Fuller, coauthors of more than 30 plays and the guiding forces of a professional acting company in Lancaster, Pa. Their drama about a crime of passion in Omaha premiered at the Actors Theater of Louisville, where it was co-winner of the 1982 Great American Play Contest. The New York production was staged by Marshall W. Mason, who has accumulated an awesome list of recognitions in the course of presenting more than 80 world premieres.

Unfortunately, these bona fides matter little in the present circumstances. As always, the play's the thing that counts. And ''Full Hookup'' counts for scarcely more than lurid sensationalism. The plot pursues a course from marital strife to uxoricide. In a preposterous denouement, the victim's irrational mother - a character misnamed Rosie - mentally obliterates the crime and claims the murderer for her son.

Taking advantage of the play's vernacular style, Jacqueline Brookes and Steve Bassett bring a certain elementary credibility to the respective roles of the paranoid widow and her psychopathic son-in-law. The solid Circle Rep cast is completed by Sharon Schlarch as the faithless but pitiful wife, Edward Seamon as Rosie's boyfriend of sorts, and Lynne Thigpen as her longsuffering office supervisor.

David Potts has devised an ingenious unit set to accommodate the interior of Rosie's mobile home and several other Omaha locales. Laura Crow designed the costumes, and the lighting is by John P. Dodd.