Sap

1. To subvert by digging or wearing away; to mine; to undermine; to destroy the foundation of.
2. The juice of plants of any kind, especially the ascending and descending juices or circulating fluid essential to nutrition.
3. The sapwood, or alburnum, of a tree.
4. To pierce with saps.
5. To proceed by mining, or by secretly undermining; to execute saps.
6. To make unstable or infirm; to unsettle; to weaken.
7. 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.
8. A simpleton; a saphead; a milksop.