Answer: undermined

AnswerCrossword Clue
UNDERMINEDWeakened
UNDERMINEDSabotaged, in a way
UNDERMINEDSubverted stealthily
underminedUNDERMINE, to dig beneath (eg a wall) in order to make it fall also UNDERMINDE
underminedDig or excavate beneath (a building or fortification) so as to make it collapse
underminedErode the base or foundation of (a rock formation)
underminedDamage or weaken (someone or something), esp. gradually or insidiously