What does "nerdy" mean?

Excuse me, could you clarify for me what exactly the term "nerdy" is intended to convey? Is it a pejorative term used to describe someone who exhibits an excessive interest in intellectual or technological pursuits, or is it simply a descriptive word that highlights a person's passion and dedication to a particular area of study or hobby? I'm curious to understand the nuances and connotations associated with this word in contemporary society.