DCHP-1 Online
Anti-Unionist Hist. 
1 n. a person opposed to the union of Upper with Lower Canada.
- 1822 We are aware that in regard to petitioners, the Anti-Unionists will have the greater number; but those who are friend to the Unions, the better arguments.
- 1848-1866 The Canadians of French descent, were almost to a man anti-unionists; those of British origin were, for the greatest part, unionists.
2 n. a person opposed to Confederation.
- 1864 We caution anti-Unionists on the island to beware.
- 1868 He censured the course of the Administration as having been ill-advised and hasty; it had created great dissatisfaction in the Maritime Provinces causing strong friends of Union, to become anti-Unionists.
- 1822 We are aware that in regard to petitioners, the Anti-Unionists will have the greater number; but those who are friend to the Unions, the better arguments.