n. 25B6; verb FOIL, frustrate, baulk, stand in the way of, forestall, derail, dash; stop, check, block, prevent, defeat, impede, obstruct, snooker, hinder, hamper; spike someone's guns; informal put paid to, put the kibosh on, do for, stymie; Brit. informal scupper, queer someone's pitch.
facilitate.