adamant, adamantine, cast-iron, dour, firm, flinty, grim, hard, hard-core, immovable, immutable, implacable, impliable, inductile, inexorable, inextensible, inextensile, inextensional, inflexible, intractable, intractile, intransigent, iron, irreconcilable, irresilient, nonelastic, nonstretchable, relentless, rigid, rigorous, rock-ribbed, steely, stern, stiff, stubborn, unaffected, unalterable, unbending, unchangeable, uncompromising, unextendible, unextensible, unflexible, ungiving, unlimber, unmalleable, unmoved, unpliable, unpliant, unrelenting, untractable, unyielding
softness, pliableness, flexibility, pliancy, pliability, sequacity, malleability, ductility, tractility, extendibility, extensibility, plasticity, inelasticity, flaccidity, laxity, penetrability, clay, wax, butter, dough, pudding, alumina, argil, cushion, pillow, feather bed, down, padding, wadding, foam, mollification, softening, soft, tender, supple, pliant, pliable, flexible, flexile, lithe, lithesome, lissom, limber, plastic, ductile, tractile, tractable, malleable, extensile, sequacious, inelastic
, aluminous, remollient, yielding, flabby, limp, flimsy, doughy, spongy, penetrable, foamy, cushiony, flaccid, flocculent, downy, edematous, oedematous, medullary, argillaceous, mellow, soft as butter, soft as down, soft as silk, yielding as wax, tender as chicken.
inelasticity, want of elasticity, absence of elasticity, inelasticity, unyielding, inelastic
, inflexible, irresilient.