Spartan, Spartanic, acerb, acerbic, acid, acidulous, acrid, acrimonious, alum, amaroidal, ascetic, asperous, austere, authoritarian, biting, bitter, bitter as gall, brisk, caustic, clamp, coarse, collapsible, compactable, compressible, compressor, constrictor, constringent, consumptive, contractible, contractile, contractional, contractive, contractor, cutting, deflationary, demanding, double-edged, dour, edged, escharotic, exacting, exigent, fierce, foldable, grim, hard, harsh, incisive, inclement, irritating, keen, meticulous, mordacious, mordant, mortified, nose-tickling, penetrating, piercing, pincer, piquant, poignant, puckery, pungent, restorative, rigorous, roborant, rough, rugged, scathing, severe, sharp, sour, stabbing, stern, stinging, strict, strident, stringent, styptic, styptic pencil, tart, tough, trenchant, ungentle, unsparing, vehement, violent, virulent, vise, vitriolic