pre-empt v.

also preempt, 1830, "secure (land, etc.) by pre-emption, occupy (public land) so as to establish a pre-emptive title to it," a back-formation from pre-emption or pre-emptive, originally American English. In the broadcasting sense of "set aside (a program) and replace it with another" it is attested from 1965, American English, a euphemism for "cancel." Related: pre-empted; preempted.