Bella Spewack, co-author with her late husband, Samuel, of a string of wacky comedies for Broadway and film - including such hits as ''Boy Meets Girl'' and the Tony Award-winning ''Kiss Me, Kate'' - died Friday night at her home in Manhattan. She was 91 years old.
''She was an original,'' said Lois Elias, a friend of Mrs. Spewack for 30 years. Mrs. Spewack had no survivors. Her husband died in 1971. ''She never thought like other people,'' Mrs. Elias said. ''She was witty, sharp, but with a quixotic approach to life, a great concern for others.'' At the same time, Mrs. Elias added, ''She was a very good businesswoman; the one who made all the arrangements for the productions.''
Mrs. Spewack, whose maiden name was Bella Cohen, was born in the Transylvania region of what is now Romania, and brought to the United States as an infant.
Radical, Pacifist Views
Growing up on the East Side of Manhattan, Mrs. Spewack graduated from Washington Irving High School in 1917. She soon went job hunting, but was turned down time after time as she sought any job available, preferably at a newspaper.
Eventually, the Yorkville Home News hired her as a writer and, soon after, her radical, pacifist views brought her to The New York Call, a socialist newspaper.
Her work apparently caught the attention of Samuel Spewack, then a young reporter for The World. ''Sam really fell in love with my writing,'' Mrs. Spewack said at the time of her husband's death. The Spewacks were married in 1922 and, after spending several years together as correspondents in Moscow, they launched a writing collaboration that eventually spanned four decades.
Their comedy was almost always madcap, verging on slapstick and knock-about farce. It was often peopled by the harassed, the rattle-brained, the blunder-prone and the pompous, among other cartoon-like characters.
Names Up in Lights
Almost every other year, from the 1930's through the 1950's, the names of Spewack works went up in lights on Broadway: ''Clear All Wires,'' in 1932; ''Spring Song,'' in 1934; ''Boy Meets Girl,'' in 1935; ''Leave It to Me,'' in 1938; ''Two Blind Mice'' and ''Kiss Me, Kate,'' both in 1949, and ''My Three Angels,'' in 1953.
Among the movies written by the Spewacks were ''The Nuisance,'' ''Three Loves Has Nancy,'' ''The Gay Bride,'' ''The Cat and the Fiddle,'' ''Weekend at the Waldorf'' and ''My Favorite Wife.''
''Clear All Wires,'' based on their experiences as reporters in Moscow, was the Spewacks' first big break on Broadway, premiering in 1932. Six years later, it was turned into a musical under the title, ''Leave It to Me,'' with a score by Cole Porter. The show, which included the song, ''My Heart Belongs to Daddy,'' introduced a new young star to Broadway - Mary Martin.
In ''Boy Meets Girl,'' which opened in New York on Nov. 27, 1935, and ran for 669 performances, the Spewacks wrote about a fictional writing team, Benson and Law. The script included an exchange that has slipped into common usage.
'Boy Meets Girl'
''Listen,'' Benson says. ''I've been writing stories for 11 years. Boy meets girl. Boy loses girl. Boy gets girl.''
''Kiss Me Kate,'' a takeoff of Shakespeare's ''Taming of the Shrew,'' with a score by Mr. Porter, ran for 1,077 performances in New York and won a Tony Award, as well as a Page One Award, for the Spewacks in 1949. The critic, Brooks Atkinson, wrote that ''Kiss Me, Kate,'' had ''the best musical comedy book of the year.''
The Spewacks had their share of flops. But, in 1955, on the night after a play called ''Festival'' received a chilly reception from the critics, Mrs. Spewack - a tiny, round woman -fought back. She marched onto the stage during curtain calls and appealed to the audience to go tell their friends if they liked the show.
''Having a failure isn't such a dreadful thing,'' she told an interviewer. ''But 'Festival' is a good, clean show, and when I heard the audience laughing and applauding, I felt it must be something they wanted.''
Mrs. Spewack then went on a dozen radio and television programs, defending ''Festival.'' And the show was extended, if only for several more weeks.