Word: severest

Reference

acute, very bad, serious, grave, critical, dreadful, terrible, awful, dangerous, parlous, life-threatening, grievous, fierce, violent, strong, powerful, intense, tempestuous, turbulent, harsh, bitter, cold, bleak, freezing, icy, arctic, extreme, brutal, excruciating, agonizing, unbearable, intolerable, splitting, pounding, screaming, difficult, demanding, tough, arduous, formidable, exacting, rigorous, punishing, onerous, grueling, scathing, sharp, savage, scorching, devastating, trenchant, caustic, biting, withering, extortionate, excessive, unreasonable, inordinate, outrageous, sky-high, stiff, punitive, stern, hard, inflexible, uncompromising, unrelenting, merciless, pitiless, ruthless, draconian, oppressive, repressive, cruel, dour, grim, forbidding, disapproving, unsmiling, unfriendly, somber, stony, steely, frosty, plain, simple, austere, unadorned, unembellished, unornamented, stark, spartan, ascetic, clinical, uncluttered, wicked, knockout