The colonists called the British soldiers Red Coats. This is because of the uniforms they wore, which were red. The British called the colonists Yankees.
If you mean the American colonists who were supporters of the British, they were called "Tories (singular - Tory)" or "Loyalists".
The British called the colonist traitors because they refused to obey the kings orders. The British also called them rebels.
Treason
Loyalists
rebellion
boycott
Rebel
Tory(s).
Loyalists, Also, Tories.
"No taxation without representation!" ~James Otis
The British were taxing the colonists without representation in Parliament.
What changed the colonists ideas about British later