A grievance is a complaint.

A grievance is a complaint. … Often a grievance is a complaint about something that breaks a rule or a law.
Three Types of Grievances. One person grieves that a management action has violated their rights under the collective agreement. Examples include discipline, demotion, harassment, improper classification or denial of earned overtime. Investigate and help the member with the grievance.
.

While the term “Grievance Redressal” primarily covers the receipt and processing of complaints from citizens and consumers, a wider definition includes actions taken on any issue raised by them to avail services more effectively.