Here I will list some words/phrases/quotes that I find useful, interesting or euphonious.

reticent uncommunicative in speech; restrained in expression.
sangfroid Composure in the face of difficulty or danger. From the French "cold blood"
savoir-faire The ability to say or do the right or graceful thing.
recondite dealing with difficult subject matter; esoteric; obscure.
febrile feverish
liminality a state of being between things, neither here nor there.
sachlich (German) objective, matter-of-fact. Mundane(?)
oblique neither parallel nor perpendicular; indirect; misleading.
trenchant forceful, efective
dietrologia the "science" of what is behind public events.
Symbolic Order The social world of linguistic communication, intersubjective relations, knowledge of ideological conventions, and the acceptance of the law. More here
soi-disant self styled
de trop (French) too much, excessive.
pulchritude Great physical beauty (especially of a woman)
bête noire One that is particularly disliked or that is to be avoided
distaff characteristic of or peculiar to women
lothario a selfish successful womanizer
emetic vomit inducing
Flâneur A detached pedestrian observer of a metropolis. But best to see the rest of this Wikipedia article: http://en.wikipedia.org/wiki/Fl%C3%A2neur
soignee polished and well-groomed; showing sophisticated elegance
genau (German) exactly, precisely.
manqué having failed to achieve ambition; falling short of hopes or expectations.
pandiculate yawn
laowai (Mandarin Chinese) foreigner
postlapsarian relating to the time after the fall of man (biblical)
oneiric of, pertaining to or suggestive of dreams; dreamy
legerdemain sleight of hand
cabron (Spanish) literally goat but really an insult. Козёл.