how do you keyword stuffing?

Keyword stuffing can often mean two things. The first is that you are cramming lots of keywords, sometimes unrelated in a post in the hope that it will rank better. Stuffing lots of keywords that are searched a lot into your web page that is about something completely different. 

I have often seen people use keyword stuffing to describe the process of using too much of the same keyword on a page. So if you are trying to target the term "ladies fashion" if you try to make sure every single sentence on the site uses this keyword, people might say that you are keyword stuffing.