A boycott is a refusal to buy, sell, or otherwise trade with an individual or business who is generally believed by the participants in the boycott to be doing something wrong.
This wrong can be stated in any terms, and is not always one that is widespread. A boycott may be oriented towards shaming offenders rather than punishing them economically, depending on its duration and scope. When long-term and widespread, a boycott is just one of many tactics in moral purchasing.
Instances of the use of boycotts are their use by African Americans during the US civil rights movement; the United Farm Workers union grape and lettuce boycotts; the American boycott of British goods at the time of the American Revolution; the Indian boycott of British goods organized by Mohandas Gandhi; and the Arab League boycott of Israel and companies trading with Israel.
A boycott is normally considered a one-time affair designed to correct an outstanding single wrong. When extended for a long period of time, or as part of an overall program of awareness-raising or reforms to laws or regimes, a boycott is part of moral purchasing, and those economic or political terms are to be preferred.
Most organized consumer boycotts today are focused on long-term change of buying habits, and so fit into part of a larger political program, with many techniques that require a longer structural commitment, e.g. reform to commodity markets, or government commitment to moral purchasing, e.g. the longstanding boycott of South African businesses to protest apartheid. These stretch the meaning of a 'boycott'.
Another form of consumer boycotting is substitution for an equivalent product; for example Mecca Cola.