Definitions
1.NounAgent noun of forestall: one who, or that which, forestalls.
One who preemptively purchases goods in order to drive up their market price for resale.
2.NounOne who preemptively purchases goods in order to drive up their market price for resale.
3.NounA device that overrides an automatic brake signal.
4.NounOne who obstructs a road, especially in order to intercept traffic.