undermine

/ˌʌndərˈmaɪn/
verb
  1. To make something weaker or less effective, often gradually or secretly.
    • The scandal undermined the public's trust in the government.
    • Lack of sleep can undermine your ability to focus.
    • Constant criticism can undermine a person's confidence.
  2. To dig or wear away the ground beneath something, making it collapse.
    • Tree roots can undermine the foundation of a house.
    • The tunnel undermined the road above, leading to a sinkhole.
    • The river's current undermined the bank, causing it to crumble.