|Origin:||preemption (17-21 centuries), from Medieval Latin praeemere 'to buy before'|
pre-empt , preempt [transitive]
to make what someone has planned to do or say unnecessary or ineffective by saying or doing something first:
The deal pre-empted a strike by rail workers.
2 American English
to replace a television show with a special programme or report:
Regular programming was preempted by a report on the war.
—pre-emption noun [uncountable]