Inequity refers to (1) injustice or unfairness, or (2) an instance of injustice or unfairness. It’s an antonym of equity, which denotes justice, fairness, or balance. Iniquity is closely related—both words ultimately derive from the Latin aequus, meaning equal—but it refers to extreme injustices, gross immorality, or acts regarded as sinful. An inequity might be a minor injustice or a small instance of unfairness, while iniquities are by definition very large or especially heinous.
Iniquity appears often in the phrase den of iniquity, referring to a place where immoral or wicked things happen. A Google Books search uncovers several instances of this phrase from the 19th century (and none from before 1800), but we find no good information on how the phrase came about.
Nearly half of those who die are “vulnerable road users” – pedestrians, cyclists, motorcyclists and passengers using unsafe public transport. This inequity is most apparent in developing countries. [Guardian]
The new hotel and casino, however, will have to jostle its way into the increasingly crowded den of upscale, sanitized iniquity that is Las Vegas. [New York Times]
Slavery was ended, but racial inequity was not. [Newsday]
The diabolical iniquity of blowing up scores of peaceful football fans watching the World Cup final might be thought to be self-evident. [Telegraph]
While people of African descent throughout the Americas tend to be concentrated in poor living conditions, health inequities can’t be attributed solely to poverty. [Baltimore Sun]