v.tr. 1 act in advance of in order to prevent. 2 anticipate (the action of another, or an event). 3 anticipate the action of. 4 deal with beforehand. 5 hist. buy up (goods) in order to profit by an enhanced price. forestaller n. forestalment n.
[ ME in sense 5: cf. AL forestallare f. OE foresteall an ambush (as FORE-, STALL) ]