sap

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. Any juice.
4. Vitality.
5. A naive person; a simpleton

1. To drain, suck or absorb from (tree, etc.).
2. To exhaust the vitality of.

noun

A short wooden club; a leather-covered hand weapon; a blackjack.

verb

To strike with a sap (with a blackjack).

noun

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.

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.
4. To gradually weaken.

   he saps my energy

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