Bellyaching is a common term used to describe a feeling of constant complaints, grumbling or grievances. There are several other synonyms that can be used interchangeably with this word, depending on the context. Some commonly used synonyms include whining, moaning, griping, whimpering, grumbling, grunting, groaning, muttering, and kvetching. Whether you are talking about complaints about a particular situation, a specific person, or about life in general, these words convey a sense of dissatisfaction or displeasure. While these synonyms can be used interchangeably, each has its own nuances and connotations, so it is important to choose the one that best fits your intended meaning.