Hircocervus

Meaning: as the OED says "A fabulous creature, half goat, half stag." They are of course using fabulous meaning 'out of fable' but I like the ambiguity.

Usefulness: 2 (Perhaps as an insult? Unless you happen to be haunting the halls of Winchester College, of course.)

Logofascination: 2 (The name is from the Latin for billy-goat and stag; another name is the tragelaph, from the Greek for the same creatures.  The genus to which Kudu belong are called Tragelaphus for this reason.)

In the wild: Michael Quinion found it in Umberto Eco, and has written it up here, and as mentioned in both that and the Wikipedia article, the hircocervus comes to us via philosophy. Plato introduced it as an example* and Aristotle takes it further; if you have the brain-power you can read up on the goat-stag in philosophy here.  It also makes a brief appearance in my favourite passage of The Horologicon; the hircocervus is one of the midnight creatures who gather around.

Tragedy

Meaning: Etymologically, the song of the billy-goat. No, really. Here's Cotgrave with a more traditional* definition:

a statelie Play whose conclusion is dolefull, and doubtfull.

Usefulness: 2 (Very useful, but downgraded due to overuse.)

Logofascination: 1 (I'm sure some of you knew this etymology already, but it's just such a great story. Plus, goats. The OED entry refers to Mr Flickinger's article from 1913, available here if you're after 20 pages of philology on the matter. It should be pointed out that the OED entry hasn't been updated since 1913, so there may well be more recent scholarship on the matter.  For those of you who haven't heard it before, tragedy is from the Greek for male goat - tragos - and song, but no-one can really agree on the reason for this.)

In the wild: See if you can find a newspaper that doesn't use it.

Capricious

Meaning: You probably already know the meaning of this word, but Cotgrave defines caprice as:

A humor, caprichio, giddie thought, fantasticall conceit; a suddaine will, desire, or purpose to doe a thing, for which one hath no (apparent) reason.

I rather like the cynicism of that (apparent). Caprichio was a synonym for caprice, but now survives only in music.

Usefulness: 1 (Although if you wish to substitute giddie thought from now on, I won't blame you.)

Logofascination: 1 (It's a goat word! Probably! In fact, according to etymonline it's either from the Latin for wild goat, or a word about people with curly hair, and how can you not love that? I had a lightbulb moment when someone at work used it this week, and unlike a lot of etymological lightbulbs, this one was correct! Probably! Goats have a suprisingly strong influence on etymology, so I'm erring in their favour.)

Acrocomic

Meaning: long-haired

Usefulness: 2 (The best use I've come up with so far is as an impressive sounding New Year's resolution: "I'm thinking of being more/less acrocomic in 2013.")

Logofascination: 1 (From Greek meaning hair on the crown or tip, which allows the OED to sneak a goat reference into the etymology:  "in Hellenistic Greek also having hair at the tip, like a goat's chin". Acro- applies to extremities - heights, tips, beginnings - and thus turns up in acronym, acropolis and acrostic.)

Hirquitalliency

Meaning: From the best known passage of Sir Thomas' own writing, and possibly his most popular word, I don't think anyone knows exactly what hirquitalliency means. The OED itself avoids giving a definition - it is sometimes misquoted as defining it as 'having or acquiring a strong voice', but the 'strong voice' reference is in the etymology. The careful homework over at Laudator Temporis Acti brings us closer to the meaning of this word: I suggest you go and read that and then come back (don't look at the archives: you can read those later).

Done? Right. The hirqui- is obviously a reference to goats, and we've seen what their reputation is like. I think Corbett's 'delighted shouts' is close to the meaning, bearing in mind the context.  My personal theory is that Sir Thomas is playing on the difference between the sense and the impression of the word, as he does the contrast between the geometric imagery of sundials and the 'cobweb slenderness of his Cyllenian vestments', between discussions of purity and digressions into the rules of grammar.  The Latin twirls and fancies of the language suggest the delicate cobwebbery and obfuscation of the romance, but the loud, lusty, Rabelaisian reality is present in the meaning and allusions - the heroine's cries may well be goat-like, but they are also pleased. 

Even if I am wrong, I think anyone using it to mean merely 'strong voiced' should think carefully about the reference to goats and the original - and so far only - citation for this word.

Usefulness: 1

Logofascination: 1 (this should probably be labelled 1A, or 1 Prime: I think this is the word that started my fascination with Sir Thomas and all his works, and although it's not currently my favourite - I'm terribly fickle - it is the reason I've discovered all of the others.)

Bouquiner

Meaning: Cotgrave tells us:

To grow hairie about the privities; also, to be as lascivious, or smell as ranke, as a goat; also, to be bookish, or, to read much in old bookes.

Usefulness: 1 (Too. many. jokes.)

Logofascination: 1 (And I'm not just being childish*. This French word apparently still means bookish, with an emphasis on old books, and may retain lascivious as a second sense. Here's my best theory; please bear in mind that I am now venturing into French etymology based almost entirely on wiktionary.** While the French have livre for book, they also borrowed from the Dutch to come up with bouquin, little book or old book, depending on whether you are feeling diminutive or pejorative. Meanwhile, bouc, meaning male goat, became the pejorative bouquin, old goat, and, voila, bouquiner means bookish or buckish, as you please.)

Billibodring

Meaning: Williams suggests that this means 'phallic jousting', hypothesising that the billi element is related to billy-goats (notoriously lustful), and the bod a shortened bourd, which has two meanings: jesting or banter, or playful jousting.* As an Urquhartian original, meaning and etymology is speculative; you could make up your own.

Usefulness: 1 (metaphorically - think of all those situations where guys are attempting to out-bloke each other. "If you two are done with the billibodring, can we get the meat off the barbecue?" "The meeting was pointless; the suits spent the entire time billibodring." "Dinner was awful, but the guys were billibodring about their cellars, so we had some incredible wine.")

Logofascination: 1