Preempt

Preempt (also spelled "Pre-empt") is a bid in contract bridge whose primary objectives are (1) to thwart opponents ability to bid to their best contract, with some safety, and (2) to fully describe one's hand to one's partner in a single bid. A preemptive bid is usually made by jumping, i.e. skipping one or more bidding levels. Since it deprives the opponents of the bidding space, it is expected that they will either find a wrong contract (too high or in a wrong denomination) of their own, or fail to find any. A preemptive bid often has the aim of a sacrifice, where a partnership bids a contract knowing it cannot be made, but assumes that (even when doubled), the penalty will still be smaller than the value of opponents' bid and made contract.

Whenever you can describe your hand completely with a single bid, you should do so. —Dean Panagopoulos, Bridge Teacher and Director, The Bridge Spot, Woburn, Massachusetts