From The Collaborative International Dictionary of English v.0.48 [gcide]:
Injustice \In*jus"tice\, n. [F. injustice, L. injustitia. See
In- not, and Justice, and cf. Unjust.]
1. Lack of justice and equity; violation of the rights of
another or others; iniquity; wrong; unfairness;
imposition.
[1913 Webster]
If this people [the Athenians] resembled Nero in
their extravagance, much more did they resemble and
even exceed him in cruelty and injustice. --Burke.
[1913 Webster]
2. An unjust act or deed; a sin; a crime; a wrong.
[1913 Webster]
Cunning men can be guilty of a thousand injustices
without being discovered, or at least without being
punished. --Swift.
[1913 Webster]
From WordNet (r) 3.0 (2006) [wn]:
injustice
n 1: an unjust act [syn: injustice, unfairness, iniquity,
shabbiness]
2: the practice of being unjust or unfair [syn: injustice,
unjustness] [ant: justice, justness]