preempt in WordNet English dictionary

1. take the place of or have precedence over
   "live broadcast of the presidential debate preempts the regular news hour"; "discussion of the emergency situation will preempt the lecture by the professor"
   preempt  displace 
   
2. acquire for oneself before others can do so
   preempt 
   
3. make a preemptive bid in the game of bridge
   preempt 
   
4. gain possession of by prior right or opportunity, especially so as to obtain the right to buy (land)
   preempt 
   

1. a high bid that is intended to prevent the opposing players from bidding
   preemptive bid  pre-empt  preempt