sapping
verb (present participle)UK /ˈsæp.ɪŋ/
US /ˈsæp.ɪŋ/
Making someone or something weaker little by little.
The hot sun was sapping his energy during the long hike.
OTHER MEANINGS
2. Cutting into or removing the sap from a tree.
They were sapping the maple trees to collect syrup.
3. Digging a trench or tunnel toward an enemy position.
The soldiers were sapping under the castle wall.
4. The act of gradually destroying something such as confidence or strength.
Constant criticism was sapping her confidence.