Undermine (3)
'undermine' is the definition.
(I know that sap is a more specific form of the action the undermine)
This is all the clue.
(Other definitions for sap that I've seen before include "Exhaust" , "Plant juice for silly ass" , "Charlie" , "Weak foolish person" , "Fluid in plant stems" .)
'undermine' is the definition.
(I know that undermine can be written as subvert)
This is all the clue.
(Other definitions for subvert that I've seen before include "Cause the downfall of; undermine" , "Morally corrupt" , "Overthrow - corrupt" , "upset" , "Sabotage" .)
'undermine' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for erode that I've seen before include "Corrode" , "Wear away with weather" , "Gradually destroy" , "Grind down" , "Become ground down or deteriorate" .)