Homonym: Curmudgeon (Grump)
A "curmudgeon" is a term used to describe a person who is often irritable, grouchy, or difficult to please. This individual typically displays a cynical attitude and may express dissatisfaction with the world around them. Curmudgeons are often seen as grumpy old men, but the term can apply to anyone who frequently complains or shows a lack of enthusiasm.
Despite their negative demeanor, curmudgeons can sometimes possess a wealth of wisdom and experience. Their critical perspective may stem from a desire for improvement or a deep-seated concern for societal issues. While they may be hard to please, their insights can be valuable in discussions about topics like society, culture, or human behavior.