Mien and taciturnity are not so unusual but I came across them together recently in the same sentence and although I could tell you what mien is easily enough, I would struggle a little with taciturnity. The sentence is "Every one in Starkfield knew him and gave him a greeting tempered to his own grave mien; but his taciturnity was respected and it was only on rare occasions that one of the older men of the place detained him for a word." The sentence is from near the beginning of Ethan Frome by Edith Wharton.
Mien is, of course, face or look. It's a bit of a literary word and comes up in R L Stevenson's famous book in the sentence "The middle one of the three windows was half-way open; and sitting close beside it, taking the air with an infinite sadness of mien, like some disconsolate prisoner, Utterson saw Dr. Jekyll ..."
Taciturnity derives from a word for silence and means incommunicative (I'd thought it meant obtuse or difficult to be honest). See W Somerset Maugham Of human bondage "Perhaps his taciturnity a contempt for the human race which had abandoned the great dreams of his youth and now wallowed in sluggish ease; or perhaps these thirty years of revolution had taught him that men are unfit for liberty, and he thought that he had spent his life in the pursuit of that which was not worth the finding."
Taciturnity derives from a word for silence and means incommunicative (I'd thought it meant obtuse or difficult to be honest). See W Somerset Maugham Of human bondage "Perhaps his taciturnity a contempt for the human race which had abandoned the great dreams of his youth and now wallowed in sluggish ease; or perhaps these thirty years of revolution had taught him that men are unfit for liberty, and he thought that he had spent his life in the pursuit of that which was not worth the finding."
