"Undressed" tag

I noticed the undressed tag a moment ago, and I fail to see what it's for. I thought it might be a tag for images where you can see everything (basically nude), their clothes are only partially on. Even then it doesn't seem to fit. It doesn't have a wiki either. Any suggestions? There's only 24-25 posts in the tag.

As far as I know, the purpose of undressed seems to be already covered by clothes_off, whose wiki says:

Tag when a character is in a state of undress and the missing article(s) of clothing can be seen in the image.

Aliased to clothes_off