sap

The watery fluid that circulates through a plant, carrying food and other substances to the various tissues.

To undermine the foundations of (a fortification).

A leather-covered bludgeon with a short, flexible shaft or strap, used as a hand weapon.

To hit or knock out with a sap.

A covered trench or tunnel dug to a point near or within an enemy position.

Health and energy; vitality.

A foolish or gullible person.