highly significant or important especially bringing about or marking the beginning of a new development or era; "epochal decisions made by Roosevelt and Churchill"; "an epoch-making discovery"
declare null and void; make ineffective; "Cancel the election results"; "strike down a law"
postpone indefinitely or annul something that was scheduled; "Call off the engagement"; "cancel the dinner party"; "we had to scrub our vacation plans"; "scratch that meeting--the chair is ill"
make up for; "His skills offset his opponent's superior strength"