Misuse of these two words is rare, but they’re worth a second look.

Problem:
The nouns “iniquity” and “inequity” are not synonyms.

Explanation:
The primary definition of the noun “iniquity” is gross immorality or wickedness. For example, identified iniquities of the sinners would be appropriate. The primary definition of the noun “inequity ” is lack of equity or fairness. For example, identified inequities in the public-education system would be appropriate.

Solution:
Use “iniquity” when you want to refer to sin, depravity, or evildoing; use “inequity” when you want to refer to unfairness.