transitive verb

1. to prevent or hinder by doing something ahead of time
2. to act in advance of; get ahead of; anticipate
3. to interfere with the trading in (a market) by buying up goods in advance, getting sellers to raise prices, etc.
4. Obsolete
   1. to intercept
   2. to obstruct by force

Etymology: ME forestallen < forestal, ambush < OE foresteall: see fore & stall