n. & v.
n. 1 the vital juice circulating in plants. 2 vigour; vitality. 3 = SAPWOOD. 4 US sl. a bludgeon (orig. one made from a sapling).
v.tr. (sapped, sapping) 1 drain or dry (wood) of sap. 2 exhaust the vigour of (my energy had been sapped by disappointment). 3 remove the sapwood from (a log). 4 US sl. hit with a sap. sap-green n. 1 the pigment made from buckthorn berries. 2 the colour of this.
adj. of this colour. sapful adj. sapless adj.
[ OE sp prob. f. Gmc ]