Final answer:
In George Orwell's '1984', the character Winston thought of pushing off a cliff was Julia. This action symbolizes the tension and mistrust prevalent in the Party-dominated society of the novel.
Step-by-step explanation:
In George Orwell's novel 1984, the character that Winston thought of pushing from a cliff was Julia. This thought occurred before Winston got to know her better and before they developed a complex relationship that was based on their mutual disdain for the Party's oppressive regime. The moment reflects the harsh realities of living under a totalitarian government where even thoughts are monitored and controlled.