Negates

16 clues
Denies
Cancels
Nullifies
Rules out
Cancels out
Invalidates
Contravenes
Proves false
Countermands
Disestablishes
Renders invalid
Brings to naught
Gives the lie to
Makes ineffective
Denies the truth of
Makes null and void
Similar answers:
Abates
Abbreviates
Abdicates
Abednego
Ablates
Abnegate
Abnegated
Abnegates
Abnegative
Abnegator
Abnegators
Abominates
Abrogates
Accelerates
Accentuates
Acerbates
Acesatest
Acetates
Achates
Activates