To boycott means to stop buying or using the goods or services of a certain company or country as a protest; the noun boycott is the protest itself.
This noun comes from the name of Charles C. Boycott, an English land agent in 19th-century Ireland who refused to reduce rents for his tenant farmers. As a result, the local residents did not want to have any dealings with him. Boycotts are an effective way to use your spending dollars to effect change.
a group’s refusal to have commercial dealings with some organization in protest against its policies
refuse to sponsor; refuse to do business with