A word used to describe devotees of J.R.R.Tolkien and his works. Tolkienists study the works of Tolkien, his languages, often belong to online or real-life communities, run their own websites (see TolkienSites)
Although the definition above may seem to be precise, people tend to disagree on what the real tolkienist is. Discussions over this topic arise in many online communities, where the issue of "real" vs. "unreal" is always ambiguous.
Some of the older fans, especially those who belong to the first generations of Tolkien's readers, tend to despise enthusiasts who often refer to themselves as "Lord of the Rings fans", leaving out the Tolkien element. Surely, these often joined the fandom after seeing the films, and even though many read the books afterwards, only some of them turn into devoted fans of the Author. LotR films are, in general, either a passing fashion or a future lifetime hobby for the novice fans.
What is more, there are people who claim that without reading UT, HoME, Letters and all the essays in addition to the main works you cannot claim yourself a tolkienist. As opposed to these, there are fans who devote their time to a single work - most often LotR, - or at least concentrate on it after reading other books. Of course, there is also a category of fans who read Tolkien basically because they are into fantasy or sci-fi and Tolkien is one of the most famoust authors, or they need to get acquainted with the resource of so many RPG characters and places used in modern games.
All in all, it is up to you whom you call "a tolkienist", but one thing is definitely required - enjoyment of what you are doing.