Curmudgeon is a word that connotes negativity, grumpiness, and cynicism. There are several synonyms for this word that capture similar meanings. One such word is a "grouch," which suggests someone who is irritable or easily annoyed. Another synonym for "curmudgeon" is "crab," which implies a person who is constantly complaining or grumbling about something. One can also use the term "misanthrope" to describe a curmudgeon, as it refers to a person who dislikes or distrusts other people. Other synonyms include "churl," "malcontent," and "sourpuss." These words all share the same qualities of being unfriendly, grumpy, and irritable.