Blunderbuss

Meaning: a gun; more detail here, if you're into that kind of thing.

Usefulness: 3

Logofascination: 2 (it's a perversion of donderbus, Dutch for thunder-gun, and the OED backs up Looper in suggesting that blunder comes into the name by way of "some allusion to its blind or random firing". A defining feature: "capable of doing execution within a limited range without exact aim." It's always nice when a scriptwriter has done their research.)

Chironomatic

Meaning: relating to chironomy, which is the art or science of what to do with your hands; John Bulwer also applied it to the Art of Manual Rhetoricke, which we much more boringly call sign language.

Usefulness: 1 (Can be applied to all those people who are happy to tell you what to do with your hands while presenting or, Google suggests, kissing. Also conductors - though it seems to have some kind of technical application to choirs - and Italians, which is how Rabelais uses it. Is a stereotype any more true because it is 400 years old?)

Logofascination: 2 (ah, humanity: concerns of chironomy bind actors, presenters, politicians, rhetoricians and, apparently, lovers, across time, space and YouTube.)

Data

Meaning: information, pieces of information

Usefulness: 2 (it's not very exciting, but we keep using it, so it must be useful.)

Logofascination: 1 (because, and only and wholly and solely because, Sir Thomas has the first citation for this word in the OED. He used it in 1645, forty-six years - yes, forty-six - before the next citation*. See graph below for evidence of how ahead of the curve Sir Thomas was on this one.  Some guy is cited under datum from 1630, in a text called Most Easie Way Finding Sunnes Amplitude, which is clearly an early example of spam.)

Metopomancy

Meaning: divination by looking at the face, particularly the lines and wrinkles on the forehead.

Usefulness: 1 ("My morning metopomancy grows grimmer by the day." "It doesn't take metopomancy to reveal that you're worried about something, my dear, particularly with those eyebrows.")

Logofascination: 1 (Rabelais, Urquhart, Cotgrave and Mrs Byrne have all used it; if that's not enough word cred for you, I don't know what is)

Eleemosynary

Meaning: charitable; related to charity, alms or alms-giving

Usefulness: 2 ('eleemosynary works' could be listed as an impressive hobby, or it could be used to obscure political arguments - see below.)

Logofascination: 1 (it's the double e, I think)

Nival

Meaning: snowy. Bonus synonym: niveous.

Usefulness: 3 (basically a straight synonym for snowy, with extra science points; could be handy in Scrabble)

Logofascination: 2 (possibly because I've never seen snow)

Auscultation

Meaning: Listening, hearkening; in particular, listening to someone's insides with a stethoscope.

Usefulness: 2 (An impressive way to describe listening to music, podcasts, gossip, or other things generally not considered Productive: "What have you been doing all afternoon?" "I did quite a bit of auscultation, actually."  n.b. may not be successful if used around doctors or nurses.)

Logofascination: 2