Loyalist BrE AmE noun
1 . a Protestant in Northern Ireland who believes that it should remain part of the UK. The people who want Northern Ireland to become part of the Republic of Ireland are called ‘Republicans’ or ‘Nationalists’.
2 . someone who was loyal to the royal family during the English Civil War
3 . someone who supported the elected government during the Spanish Civil War
4 . someone who fought with the British during the American Revolutionary War
5 . someone who supported the Union during the American Civil War
—Loyalist adjective :
the Loyalist flag/anthem