annulment, bafflement, balk, balking, buck-passing, cancellation, check, checkmate, circumvention, confounding, counterbalancing, defeat, discomfiture, disconcertion, elusion, evasion, foil, foiling, frustration, getting around, getting round, invalidation, neutralization, nullification, offsetting, outguessing, outmaneuvering, outwitting, passing the buck, the runaround, the slip, undoing, upset, vitiation, voiding