a person who complains a lot, usually about something that does not seem important to other people

They're just a lot of moaners who are never satisfied. 他们就是一群爱发牢骚的人，永远不满足。

Old people have gained a reputation for being grumpy, belligerent moaners. 人们说老年人脾气暴躁、好斗又爱发牢骚。