Veto - (noun or verb)
(1) Used as a noun, it refers to a vote that blocks a decision. (2) Used as a verb, it means ‘to refuse to approve’ something.
Source: Adapted from Merriam-Webster Dictionary
Example of Use: (1) The European Commission proposed ending the veto that member states have over EU tax matters. (2) The UK was able to veto some laws by itself.