grumbler

1. He is a grumbler.
   他是一个爱抱怨的人。
2. There's always one grumbler in every class who spends the whole time trying to stir up trouble among the others.
   每个班级总有一个爱抱怨的人花费全部时间试图在别人中间挑起事端。

noun

1. a person given to excessive complaints and crying and whining

   Synonym:    whinercomplainermoanersnivellercrybabybellyachersquawker