Definition of "undermine" in English

verb

1. To dig underneath (something), to make a passage for destructive or military purposes; to sap.

2. (figuratively) To weaken or work against; to hinder, sabotage.

   • The war efforts were undermined by the constant bickering between the allies.

3. To erode the base or foundation of something, e.g. by the action of water.

4. (philosophy) To regard an object as the sum of the parts that compose it, in object-oriented ontology.