Definition of sap

• n. - The juice of plants of any kind, especially the ascending and descending juices or circulating fluid essential to nutrition.
• n. - The sapwood, or alburnum, of a tree.
• n. - A simpleton; a saphead; a milksop.
• v. t. - To subvert by digging or wearing away; to mine; to undermine; to destroy the foundation of.
• v. t. - To pierce with saps.
• v. t. - To make unstable or infirm; to unsettle; to weaken.
• v. i. - To proceed by mining, or by secretly undermining; to execute saps.
• n. - 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.