@chriddi mentioned procrastination too and I found it interesting that the first article included procrastination under "lazy". But I don't consider procrastination as lazy - it's not a lack of willingness, it's a lack of wanting so like you say "not intrinsically motivated to do". Or maybe they're the same thing.

This being "lazy" is more of a general state, complete lack of drive, contentment with being stuck....

To me, this says that it's more to do with "energy". We're generally lazy when we never have the energy to do anything. If we've got the energy but simply don't want to, then maybe we're unmotivated.

The more I think about it, the more I think that the first article I referenced is a load of crap.