What makes a low end "tight"?

Hey everyone,

In my last submission to the feedback thread, several people called my low end tight. While that is very flattering - and it sounds positive - I have no idea, what it actually means? I just make bass following some guidelines I have picked up over the years, but never gave much thought to them. Now I'm curious - what does a tight lowend actually mean, and what is the opposite of it? (I kinda like to know, what it is I want to avoid - right now I just feel like Simba being told to stay away from the realm of shadows)