Injustice, injury, wrong, grievance are comparable when they denote an act that inflicts undeserved damage, loss, or hardship on a person.
Injustice is the general term applicable not only to an act which involves unfairness to another or a violation of his rights, but, as a collective noun, to all acts which come under this description.
Injury applies to an injustice to a person for which the law allows an action to recover compensation or specific property, or both.
Wrong is, in law, a more general term than injury for it applies not only to all injuries as just defined (private wrongs ) but to all misdemeanors or crimes which affect the community (public wrongs ) and which are punishable according to the criminal code. But in general use wrong differs little from injustice , except in carrying a stronger connotation of flagrancy or of seriousness.
Grievance applies to a circumstance or condition that, in the opinion of those affected, constitutes a wrong or that gives one just grounds for complaint.