Big Maggie. Play by John B. Keane. Directed by Donal Donnelly. An old-fashioned, oddly entertaining comedy drama about an Irish widow's determined declaration of independence has introduced New York audiences to the work of popular Irish playwright John B. Keane. The dominant - and domineering - central character of ''Big Maggie,'' at the Douglas Fairbanks Theater, is newly widowed Maggie Polpin (Robin Howard). First encountered near the grave site where her late husband is being buried, Maggie makes it clear that she has no intention of mourning the bibulous, womanizing mate who caused her so much tribulation.
Instead of indulging in recrimination, the strong-willed, sharp-tongued Maggie wastes no time in taking control of the shop and family farm that make up her estate - Polpin having died in debt. When her children demand to know about a will, Maggie explains that there is no such thing. Having caught Polpin with another woman, Maggie forced him to assign all property rights to her a year before his passing.
The human drives, the flavor, and local color of ''Big Maggie'' are vividly realized in the production staged by Donal Donnelly. The gradually disaffected offspring are well played by Kevin McGuire as the rebellious Mick, who absconds with Maggie's ready cash and takes off for England; by Robert Walsh as the grudgingly compliant younger son who chafes to get married; by Terry Finn as the light-moraled elder daughter whom Maggie forces into prosperous, respectable marriage; and by Juliana Donald as the younger daughter, whom Maggie brutally disillusions when the girl falls for a glib traveling salesman.
But it is Big Maggie and her newfound freedom that inspire Mr. Keane's deep and overriding concern.
As written and admirably played by Miss Howard, Maggie embodies feminist liberation without even bothering to define or articulate it. Perverse, sardonic , and aggressively independent, Maggie doesn't suffer fools gladly. And she has a discomfiting way of exposing other people's foolishness.
''A snail's tail is small but it's nothing to what I care about what people think of me,'' she remarks. Recalling her miserable marriage, she says: ''Pride, ignorance, and religion were like chains around me.''
Any help Maggie proposes to give her children will be strictly on her own terms. Mr. Keane concedes that the widow's mother-knows-best dictatorship may be motivated by maternal concern. But he also perceives the children's conviction that they are the victims of Maggie's harsh, self-willed domination. Left alone at the end, Maggie proves to have paid a high price for her victories. In winning, she may have lost her humanity.
Miss Howard grasps the complexities of the hard-grained widow's nature - even when Mr. Keane's plot contrivances tend to strain credulity. The actress relishes the contradictions of a woman whose bluntness is not without humor and whose perceptions are as sharp as her tongue.
''Big Maggie'' enjoys a supporting performance worthy of its rural Irish setting and character. Besides the young actors playing the children subjected to Maggie's hard-knocks parental schooling, the company at the Douglas Fairbanks includes David Huddleston as a corpulent stonecutter who takes a fancy to the handsome widow; James Handy as the glib salesman; Maura Vaughn as a village girl whom young Polpin has made pregnant; Anne Clay as the girl's calculating mother; and Scott Schofield and Hope Cameron for humorous local color.
David Potts has made efficient use of the theater's revolving stage to accommodate the play's locales. ''Big Maggie'' has costumes by Judith Dolan and lighting by Andrea Wilson.