Similar word to unsupple:

annealed, arthritic, benumbed, brittle, buckram, cemented, chilled, congealed, contracted, creaky, firm, fixed, frozen, graceless, hardened, immalleable, impliable, incompliant, indurate, inelastic, jelled, mechanical, numbed, ossified, petrified, refractory, resistant, rheumatic, rigid, set, solid, solidified, starched, starchy, stark, steely, stiff as a board, stony, taut, tense, thick, thickened, tight, unbending, unflexible, ungraceful, unsupple, unyielding, wooden