A person who hovers around a group and contributes nothing to the conversation consistently. people will try to slowly ease them away but if they do not take the hint this is when a tag along becomes a j dot/j.

It can be changed based off of the first letter of that person's name

A j dot is a weird guy/girl that doesn't speak in group conversations, a j dot usually clings to a group of people that are of a higher social status.

Other ways of saying j dot :
Jade
Jadey