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
The term "Lobsterbacks" was used by colonists to refer to British soldiers due to their distinctive red uniforms, which resembled the color of cooked lobster shells. This nickname reflected the colonists' disdain and resentment towards British rule and the military presence in the colonies. The term also served to dehumanize the soldiers, reinforcing the growing divide between the colonists and the British authorities during the lead-up to the American Revolution.
boycott
rebellion
Rebel
Tory(s).
The British were taxing the colonists without representation in Parliament.
What changed the colonists ideas about British later
"No taxation without representation!" ~James Otis