A person who exercises the power of veto or supports the use of a veto; an advocate of the possession of a power of veto, especially for some particular purpose. Formerly often specifically (now historical) (a) a supporter of a veto on the appointment of Roman Catholic bishops in Ireland; (b) a supporter of the Veto Act of the Church of Scotland; (c) a supporter of a local veto on the sale of alcohol.
local vetoist: see the first element.
Early 19th century. From veto + -ist.