A conspiracy, also known as a plot, ploy, or scheme, is a plan or agreement between people (called conspirers or conspirators) for an unlawful or harmful purpose, such as murder, treason, or corruption, especially with a political motivation, while keeping their agreement secret from the public or from other people affected by it. In a political sense, conspiracy refers to a group of people united in the goal of subverting established political power structures. This can take the form of usurping or altering them, or even continually illegally profiteering from certain activities in a way that weakens the establishment with help from various political authorities. Depending on the circumstances, a conspiracy may also be a crime or a civil wrong. The term generally connotes, or implies, wrongdoing or illegality on the part of the conspirators, as it is commonly believed that people would not need to conspire to engage in activities that were lawful and ethical, or to which no one would object.
There are some coordinated activities that people engage in with secrecy that are not generally thought of as conspiracies. For example, intelligence agencies such as the American CIA and the British MI6 necessarily make plans in secret to spy on suspected enemies of their respective countries and the general populace of its home countries, but this kind of activity is generally not considered to be a conspiracy so long as their goal is to fulfill their official functions, and not something like improperly enriching themselves. Similarly, the coaches of competing sports teams routinely meet behind closed doors to plan game strategies and specific plays designed to defeat their opponents, but this activity is not considered a conspiracy because this is considered a legitimate part of the sport. Furthermore, a conspiracy must be engaged in knowingly. The continuation of social traditions that work to the advantage of certain groups and to the disadvantage of certain other groups, though possibly unethical, is not a conspiracy if participants in the practice are not carrying it forward for the purpose of perpetuating this advantage.