noun, verb, sapped, sap⋅ping.| 1. | the juice or vital circulating fluid of a plant, esp. of a woody plant. |
| 2. | any vital body fluid. |
| 3. | energy; vitality. |
| 4. | sapwood. |
| 5. | Slang. a fool; dupe. |
| 6. | Metallurgy. soft metal at the core of a bar of blister steel. |
| 7. | to drain the sap from. |

noun, verb, sapped, sap⋅ping.| 1. | Fortification. a deep, narrow trench constructed so as to form an approach to a besieged place or an enemy's position. |
| 2. | Fortification.
|
| 3. | to undermine; weaken or destroy insidiously. |
| 4. | Fortification. to dig a sap. |

sap
|