Auction sniping (or bid sniping) is
a technique where a user in a timed online auction waits until the time limit is nearly expired before entering a bid. The other participants in the auction do not have enough time to enter a counterbid, allowing the sniper to win the auction. A sniper may enter the bids manually or use a software package to do so.
- Techopedia, "What is Auction Sniping?" (full-text).