Which term describes the act of superseding or taking something beforehand for oneself?

The term that describes the act of superseding or taking something beforehand for oneself is "preempt." This word comes from the notion of taking action in advance to prevent something else from happening or to seize an opportunity before others can. It carries the connotation of asserting control over a situation before it unfolds, which aligns perfectly with the idea of taking something for oneself prior to others.

In contrast, "anticipate" refers to the act of expecting or predicting something but does not imply taking action to seize it. "Postpone" means to delay something until a later time, which is clearly the opposite of taking something beforehand. "Subordinate" denotes placing something in a lower rank or position, which doesn't relate to the concept of taking or seizing. Therefore, "preempt" is the most fitting term for this context.