Having become known as someone who writes about this kind of thing, I was asked on Twitter the other day to explain the difference between unorganised and disorganised. It’s another one of these subtle shades of meaning, with one being more specific and the other more general – we seem to have quite a few of those in English and I do like them!
Being unorganised is all about the specific thing that is unorganised; it’s the acute version, if you like. A party where you haven’t planned any food for people to eat, an essay that has no plan to it and is that bit harder to write – that’s unorganised
Being disorganised is a general, holistic thing, more of a character point than a specific item. Following the medical analogy above, the chronic version of lack of organisation. So a disorganised person is generally chaotic and inefficient, and a disorganised committee or event is not properly planned and controlled. A disorganised desk is one in constant disarray, a disorganised essay has been written from that unorganised plan and is pretty unreadable.
I said it was subtle!