Does "nerd" include the meaning of dark and gloomy person?
No. A "nerd" is a person who lacks social skills, is typically very smart, and likes things that others may find uncool or weird. Some people may consider "nerds" to be boring individuals and not want to associate or hang out with them. Ex: The girls consider him nerdy and don't like talking to him. Ex: She is such a nerd. However, being a nerd doesn't always have a negative connotation. If you put an adjective in front of the word "nerd," it typically implies that this person has a lot of knowledge in this area. Ex: He is a computer nerd. If you have any questions about computers, just ask him and he will be able to tell you. Ex: She is such an anime nerd. She has seen almost every anime show you can think of.