He's Not There

Here is a mildly depressing article about someone who has devoted many, many thousands of hours to a game called World of Warcraft and has apparently done everything that can be done in it. Except one:

The achievement hasn't arrived without some controversy though; WoW-heads point out that technically he's still missing one illusive, event-tied achievement (called "BB King"), but he's managed to dodge it via a glitch awarding one extra, false achievement point.

The unachieved achievement is something that, apparently (I read it somewhere, and no, I don't remember where--you could look it up if you cared), was tied to a specific time or season such as Christmas and can't be replicated or redone. Not that that matters, because here's what does matter (to me):

The word "illusive" is used incorrectly.

There are three similar words that are sometimes misused by people who are not absolutely secure in their employment of the language: "illusive", "allusive", and "elusive". They do not mean at all the same thing. "Illusive" is a synonym of "illusory" and is therefore related to "illusion"; it means "unreal: not corresponding to facts or reality." "Allusive" is related to "allusion" and means "characterized by indirect reference." "Elusive", the most common of the three words and the one that was intended, means "difficult to describe or capture."

They all come from the same Latin root: "ludere", "to play", also the source of "ludicrous". "Alludere" meant in Latin "to mock; to jest" and eventually in English came to mean "to make a fanciful reference to", taking on the sense of indirect reference later. "Illudere" meant "to play with", later "to deceive", which is where the sense of the deceptive illusion comes from. And "eludere" carried the sense of "to make a fool of by escaping from." So, closely related.

But they are not the same thing!