Overlook means (1) "to fail to notice," (2) "to disregard or ignore," (3) "to rise above," (4) "to excuse": "He overlooked my mistake." "Robin is a girl who overlooks such minor matters." "My window overlooks a park." "The foreman will overlook your tardiness." Oversee means (1) "to observe secretly or unintentionally"; (2) "to direct, supervise, or manage": "Bert just happened to oversee the stolen kiss." "The superintendent is expected to oversee the performance of the entire staff."
Dictionary of problem words and expressions. Harry Shaw. 1975.