I can't seem to tell the difference between nudity and full nudity clips. Anyone know what they mean?

It's possible that the ratings are that a topless card would get the nude rating... Full nudity will be no clothes at all... but don't quote me on this... ;)

Here's a short answer........
No nudity is, of course, no nudity
Topless is naked titties or at least nipples showing
Nudity is at least no panties and sometimes no clothing but not necessarilly naked titties
Full nudity includes heavy rubbing or explicit views but not necessarily completely naked
XXX usually has some orgasmic action or penetration of some sort

It's more or less a scale of one to five in levels of explicitness

Yes, I suppose it can get a bit ***** at times and maybe my answer is quite ***** as well
The mind wobbles
;-)

I will also add that the Rating is based off the Highest level of erotic behavior, that the Clip contains.
So a clip Might be 45 seconds completely clothed, and the Model Flashes Her bare bottom for a second or two..
That would give the Clip a Nudity Rating, because seeing her bare bottom, even that briefly,
Makes that the Highest level of Erotic Behavior for that Clip.

The ratings are sometimes difficult to figure out, why the clip was rated the way it is.

Selecting an Erotic level means, you will never see anything Higher than that erotic Level..

So if you never want to see more than Toppless, you would select that as the highest level.
It doesn't mean that the entire clip will be toppless., but that there will be a toppless moment...

I'll bet your asking yourself, Why Did I ask that now...
we've ***** you even more than before.

I liked it better when they used the term "Explicit" for the term they use now which is "Full Nudity"