Injustice is a quality relating to unfairness or undeserved outcomes. The term may be applied in reference to a particular event or situation, or to a larger status quo. In Western philosophy and jurisprudence, injustice is very commonly—but not always—defined as either the absence or the opposite of justice.
The sense of injustice is a universal human feature, though the exact circumstances considered unjust can vary from culture to culture. While even acts of nature can sometimes arouse the sense of injustice, the sense is usually felt in relation to human action such as misuse, abuse, neglect, or malfeasance that is uncorrected or else sanctioned by a legal system or fellow human beings.
The sense of injustice can be a powerful motivational condition, causing people to take action not just to defend themselves but also others who they perceive to be unfairly treated. Injustice within legal or societal standards are sometimes referred to as a two-tiered system.