undermine
un-der-MINEverbMeaning to weaken gradually or secretly
Memory hook UNDER-MINE: dig beneath it. A rabbit tunnels under the sandcastle’s tallest tower, and day by day the tower leans a little more. Weakening something from underneath is to undermine it.
Constant teasing can undermine a child’s confidence.
In context Though he praised the plan in public, the manager quietly undermined it, canceling its meetings and moving its money to other projects.
Similar weaken, erode, subvert, sabotage
Opposite strengthen, support, bolster
From under + mine: to dig a tunnel beneath a wall so that it collapses.