unionist

• POS: Adjective, Noun
• HYPHEN: Un=ion=ist

CIDE DICTIONARY

unionist, n. 

•  One who advocates or promotes union; especially a loyal supporter of a federal union, as that of the United States.  [1913 Webster]
•  A member or supporter of a trades union.  [1913 Webster]

OXFORD DICTIONARY

unionist, n.
1 a a member of a trade union. b an advocate of trade unions.
2 (usu. Unionist) an advocate of union, esp.: a a person opposed to the rupture of the parliamentary union between Great Britain and Northern Ireland (formerly between Great Britain and Ireland). b hist. a person who opposed secession during the American Civil War.

Derivative

unionism n. unionistic adj.