A double standard is the application of different sets of principles for similar situations.
A double standard may take the form of an instance in which certain concepts (often, for example, a word, phrase, social norm, or rule) are perceived as acceptable to be applied by one group of people, but are considered unacceptable—taboo—when applied by another group. A double standard can therefore be described as a biased or morally unfair application of the principle that all are equal in their freedoms. Such double standards are seen as unjustified because they violate a basic maxim of modern legal jurisprudence: that all parties should stand equal before the law. Double standards also violate the principle of justice known as impartiality, which is based on the assumption that the same standards should be applied to all people, without regard to subjective bias or favoritism based on social class, rank, ethnicity, gender, religion, sexual orientation, age, or other distinctions. A double standard violates this principle by holding different people accountable according to different standards.
A policy of double standards is a situation when the assessment of the same phenomenon, process or event in the international relations depends on character of the relations of the estimating parties with assessment objects. At identical intrinsic filling of action of one country get support and a justification, and other – is condemned and punished.
The following phrase became an example of policy of double standards: "One man's terrorist is another man's freedom fighter", entered into use by the British writer Gerald Seymour in his work Harry's Game in 1975.