Oona O'Neill (1925–1991) was the fourth and final wife of actor and filmmaker Charlie Chaplin, marrying him in 1943 at the age of 18. She was the daughter of acclaimed American playwright Eugene O'Neill (often misspelled in your query as "Ugin o nill") and writer Agnes Boulton.

Key Facts about Oona O'Neill:Marriage to Chaplin: She married Charlie Chaplin (who was 54 at the time) on June 16, 1943, in California, a 36-year age difference that caused a massive scandal.
Estrangement from Father: Her father, Eugene O'Neill, strongly disapproved of the marriage to a man his own age and disowned her; he never spoke to her again.
Family: She and Chaplin had eight children together: Geraldine, Michael, Josephine, Victoria, Eugene, Jane, Annette, and Christopher.
Life in Exile: Following the cancellation of Chaplin's U.S. re-entry permit in 1952, she renounced her American citizenship in 1954 and became a British citizen, moving with her family to Switzerland.
Later Life: After Chaplin's death in 1977, she lived as a recluse and died of pancreatic cancer in 1991.
Oona O'Neill should not be confused with her granddaughter, Oona Chaplin (born 1986), who is an actress known for Game of Thrones.