Sabotage

UNDERMINE

Think of a verb that describes gradually weakening something from below, like eroding the foundation of a structure or someone's confidence.

"Sabotage" hints at deliberately weakening something, which is exactly what "undermine" means—both literally (digging under foundations to collapse them) and figuratively (eroding support or trust). The wordplay leans on the idea of mining beneath (under) to cause damage, tying the physical act to the broader sense of sabotage. It’s a straightforward definition clue where the answer mirrors the destructive intent of the clue.