Sandy Dennis, 54, the veteran character actress who won an Academy Award for her performance as the whimpering young faculty wife in "Who's Afraid of Virginia Woolf?," has died. A longtime friend said she learned of Ms. Dennis' death from her agent but didn't know when she died. The actress, who lived in Westport, Conn., with her mother, had been suffering from ovarian cancer. She made her debut in movies in 1961, playing a supporting role in Elia Kazan's "Splendor in the Grass." But she emerged as a star on Broadway, winning two Tony awards in succession for "A Thousand Clowns" and "Any Wednesday." In 1966 she won an Oscar for best supporting actress in "Who's Afraid of Virginia Woolf?," the film adaptation of Edward Albee's scathing drama. She played leads in other films, notably the teacher in a tough New York school in "Up the Down Staircase" in 1967. She won the New York Film Critics' award for that role.