Word: grimmest

stern, forbidding, uninviting, unsmiling, dour, formidable, harsh, steely, flinty, stony, cross, churlish, surly, sour, ill-tempered, fierce, ferocious, threatening, menacing, implacable, ruthless, merciless, black, dark, mirthless, bleak, cynical, dreadful, dire, ghastly, horrible, horrendous, horrid, terrible, awful, appalling, frightful, shocking, unspeakable, grisly, gruesome, hideous, macabre, depressing, distressing, upsetting, worrying, unpleasant, dreary, dismal, dingy, wretched, miserable, cheerless, comfortless, joyless, gloomy, godawful, resolute, determined, firm, decided, steadfast, dead set, obstinate, stubborn, obdurate, unyielding, intractable, uncompromising, unshakable, unrelenting, relentless, dogged, tenacious, mordant, down in the mouth, dispirited, downhearted, low-spirited, down, depressed, downcast, low, blue, inexorable, unappeasable, unforgiving, sick, sorry, drear, drab, disconsolate