v. t. [ imp. & p. p. Sapped p. pr. & vb. n. Sapping. ] [ F. saper (cf. Sp. zapar, It. zapare), fr. sape a sort of scythe, LL. sappa a sort of mattock. ] 1. To subvert by digging or wearing away; to mine; to undermine; to destroy the foundation of. [ 1913 Webster ]

Nor safe their dwellings were, for sapped by floods,
Their houses fell upon their household gods. Dryden. [ 1913 Webster ]

2. (Mil.) To pierce with saps. [ 1913 Webster ]

3. To make unstable or infirm; to unsettle; to weaken. [ 1913 Webster ]

Ring out the grief that saps the mind. Tennyson. [ 1913 Webster ]

n. [ AS. saep; akin to OHG. saf, G. saft, Icel. safi; of uncertain origin; possibly akin to L. sapere to taste, to be wise, sapa must or new wine boiled thick. Cf. Sapid, Sapient. ] 1. The juice of plants of any kind, especially the ascending and descending juices or circulating fluid essential to nutrition. [ 1913 Webster ]

☞ The ascending is the crude sap, the assimilation of which takes place in the leaves, when it becomes the elaborated sap suited to the growth of the plant. [ 1913 Webster ]

2. The sapwood, or alburnum, of a tree. [ 1913 Webster ]

3. A simpleton; a saphead; a milksop. [ Slang ] [ 1913 Webster ]

Sap ball (Bot.), any large fungus of the genus Polyporus. See Polyporus. --
Sap green, a dull light green pigment prepared from the juice of the ripe berries of the Rhamnus catharticus, or buckthorn. It is used especially by water-color artists. --
Sap rot, the dry rot. See under Dry. --
Sap sucker (Zool.), any one of several species of small American woodpeckers of the genus Sphyrapicus, especially the yellow-bellied woodpecker (Sphyrapicus varius) of the Eastern United States. They are so named because they puncture the bark of trees and feed upon the sap. The name is loosely applied to other woodpeckers. --
Sap tube (Bot.), a vessel that conveys sap. [ 1913 Webster ]

v. i. To proceed by mining, or by secretly undermining; to execute saps. W. P. Craighill. [ 1913 Webster ]

Both assaults are carried on by sapping. Tatler. [ 1913 Webster ]

n. (Mil.) A narrow ditch or trench made from the foremost parallel toward the glacis or covert way of a besieged place by digging under cover of gabions, etc. [ 1913 Webster ]

Sap fagot (Mil.), a fascine about three feet long, used in sapping, to close the crevices between the gabions before the parapet is made. --
Sap roller (Mil.), a large gabion, six or seven feet long, filled with fascines, which the sapper sometimes rolls along before him for protection from the fire of an enemy. [ 1913 Webster ]

n. See Sapodila. [ 1913 Webster ]

n. (Zool.) The sapajou. [ 1913 Webster ]

n. [ F. sapajou, sajou, Braz. sajuassu. ] (Zool.) Any one of several species of South American monkeys of the genus Cebus, having long and prehensile tails. Some of the species are called also capuchins. The bonnet sapajou (Cebus subcristatus), the golden-handed sapajou (Cebus chrysopus), and the white-throated sapajou (Cebus hypoleucus) are well known species. See Capuchin. [ 1913 Webster ]

[ Malay sapang. ] (Bot.) A dyewood yielded by Caesalpinia Sappan, a thorny leguminous tree of Southern Asia and the neighboring islands. It is the original Brazil wood. [ Written also sappan wood. ] [ 1913 Webster ]

a. Abounding in sap; sappy. [ 1913 Webster ]

n. A weak-minded, stupid fellow; a milksop. [ Low ] [ 1913 Webster ]