SAP

n. & v. --n. 1 a tunnel or trench to conceal assailants' approach to a fortified place; a covered siege-trench. 2 an insidious or slow undermining of a belief, resolution, etc. --v. (sapped, sapping) 1 intr. a dig a sap or saps. b approach by a sap. 2 tr. undermine; make insecure by removing the foundations. 3 tr. destroy insidiously. [ult. f. It. zappa spade, spadework, in part through F sappe sap(p)er, prob. of Arab. orig.]