From Longman Dictionary of Contemporary Englishpre-emptpre-empt, preempt /priˈempt/ verb [transitive] 1 FIRSTto 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 /-ˈempʃən/ noun [uncountable]→ See Verb table