The word "grumpy" describes a person who is easily annoyed or in a bad mood. Someone who is grumpy tends to be irritable and may complain or express dissatisfaction frequently. They may not be very friendly or cheerful, often showing their displeasure through their body language or tone of voice.
The word "grumpy" is believed to have originated in the early 20th century, likely derived from the word "grump," which means to complain or grumble. The exact origin of "grump" is uncertain, but it may be related to the Scottish word "grump," meaning to grumble or complain.