怨言 (yuàn yán): Complaint / Grievance (Noun) — Meaning & Stroke Order

Regarding the company's last-minute overtime arrangement, the employees have quite a few complaints in private.

Although the work is tiring, he never complains and has no grievances.

Don't you have even a single complaint about such a lengthy approval process?

Even though the tasks were heavy and the pressure immense, she never voiced any grievances to anyone.