While the Broadway season continues to suffer from malnutrition, Off Broadway's playgoers have been feasting on good theater and a diet of notable acting. The list of long-running dramatic entertainments has recently been augmented by several arrivals. From the light comedy pleasures of ''The Dining Room'' and the shared confidences of ''Sally and Marsha'' to the mordant satire of ''How I Got That Story,'' Off Broadway stages have come alive with the kind of acting that glorifies the art. Latest among the more stimulating events has been the revival of ''The Caretaker.''
The three-man cast of ''The Caretaker,'' at the Roundabout Theater illumines the dark corners of this first great Pinter success and still, after more than 20 years, one of his most substantial works. The cluttered West London attic becomes the setting for a series of intense and shifting relationships, comic inevitabilities, and personal revelations - all somehow magnified by the sense of menace that broods over the Pinter landscape.
Simply described, ''The Caretaker'' tells how brothers Aston (Anthony Heald) and Mick (Daniel Gerroll) respond to the presence of the derelict transient Davies (F. Murray Abraham).
The mentally afflicted Aston at first extends shelter to the ragged vagrant, whom he has rescued from physical injury in a cafe altercation. But owner Mick, with his mock-literate flights and complicated bullying, twigs Davies's clumsy opportunism and gives the old man (and the audience) some nasty scares.
From his first appearance, Mr. Abraham begins his detailed portrait of a loser and a hater - a mendicant whose fierce racism is part of a hostility that alienates even those who would try to help him. Mr. Abraham explores and exposes the quirks and quiddities of Davies's flawed personality - his truculent importunity, persnickety acceptance, and cringing aggressiveness. The evasiveness of Davies invites skepticism; his suspiciousness sharpens others' suspicion.
Davies attempts to play the two brothers against each other, a ploy that eventually loses him both his temporary shelter and chances of a janitorship in the scruffy premises. Yet there is a pitiful desperation in his references to the ''papers'' that might somehow establish his identity.
Mr. Gerroll gives a sharply witty performance as the mercurial Mick, whose insouciance can turn suddenly chilling. To Mr. Heald, as the slow-witted Aston, falls the long and moving account of his hospitalization. Mr. Heald's quiet and halting delivery of the speech adds yet another emotional dimension to this taut , introspective, and strangely haunting drama.
Anthony Page has directed the illuminating performance at the Roundabout, with helpful contributions from Roger Mooney (scenery), Ronald Wallace (lighting), A. Christina Giannini (costumes), and Philip Campanella (sound).