Are you trying to find just the right word for someone who’s very bad-tempered and grumpy? Curmudgeon (noun) might be just the word that you’re looking for! Dating back to at least the 16th century, this word has been used for a long time. Often referred to old people with bad temparament.
>I don’t like my new boss … he is a real curmudgeon!”
>Though I consider myself a cheery soul, this man made me look like a miserable curmudgeon in comparison to his genuine sweet manners