“Tonight’s episode has been pre-empted.” Pre-empted! How peremptory! Is it cancelled or just postponed? Wait – pre-emption is postponement? Well, that’s preposterous.
And yet there you have it. We may be tempted to think it unkempt, and perhaps a sign of contempt, for a third party to attempt to exempt itself from the usual rules and schedules. But broadcast schedules, like so many others, tend to follow the golden rule: whoever has the gold makes the rules. If someone has the money or the power, they can bump you or gazump you. They can even buy the spot before you get a chance at it.
Which is what pre-empt means. Its source (via French) is Latin prae ‘before’ and emptio ‘purchase’. Its first sense is ‘purchase a property before it is offered to another party’. Its use in broadcast started from ‘buy a time slot to keep others from using it’ and progressed to ‘cancel a planned broadcast in order to give the time to something else’ (generally something that’s worth more money, or at least will get more interest, which is largely the same thing).
Now it can be used in an even broader sense if you’re careful about it. One could raise a certain topic in conversation to pre-empt discussion of another topic; one could use a certain political manoeuvre to pre-empt a decision or action. But if you’re tempted to pre-empt, do be aware that it may provoke resemptment. I mean resentment. If your pre-emptees have enough gumption, at the resumption of business as usual – or even before it – you may in turn be gazumped or otherwise thumped. So caveat pre-emptor.