The word "preemptive" means taking action before someone else does, in order to prevent or eliminate a possible threat or problem. It is basically being proactive and addressing something before it becomes a bigger issue. Full definition
For this reason, couples are now considering couples therapy before the arrival of a child, according to this Wall Street Journal Blog article a sort of preemptive strike against possible problems in the future that could threaten an otherwise secure relationship. (theparentszone.com)
This 49 - pp report responds to critics who have defended killer robots and challenged call for preemptive ban by providing detailed rebuttals to 16 key contentions. (stopkillerrobots.org)
a freeze would prevent the deployment of some destabilizing systems, but it would also prevent the development of the new, small, single warhead, land - based missiles that would be safer than the MIRVed land - based missiles which increase fears of preemptive strikes. (religion-online.org)