disgruntled employee

Translations
недовольный сотрудник
The disgruntled employee decided to file a complaint against the company.
Недовольный сотрудник решил подать жалобу на компанию.
Definitions
A disgruntled employee is a worker who is dissatisfied or unhappy with their job, often due to perceived unfair treatment, poor working conditions, or lack of recognition, which may lead to decreased motivation and productivity.