sap

n.

  1. The juice of plants of any kind, especially the ascending and descending juices or circulating fluid essential to nutrition.
  2. The sapwood, or alburnum, of a tree.
  3. A simpleton; a saphead; a milksop.
  4. 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.

v. t.

  1. To subvert by digging or wearing away; to mine; to undermine; to destroy the foundation of.
  2. To pierce with saps.
  3. To make unstable or infirm; to unsettle; to weaken.

v. i.

  1. To proceed by mining, or by secretly undermining; to execute saps.