Moaning Myrtle is a character from the Harry Potter series who is known for her constant complaints and whining. Synonyms for moaning myrtle may include grumbler, complainer, whiner, croaker, bellyacher, griper, moaner, and kvetch. These terms all describe someone who complains or expresses dissatisfaction in a persistent and often annoying way. While some people may use these terms in a derogatory manner, it's important to remember that everyone has the right to express their feelings and concerns. However, excessive complaining can also be a sign of chronic negativity and may have a toxic impact on interpersonal relationships.