asininity blockishness body boobishness boorishness bovinity callosity callousness cloddishness concreteness crassness crudeness denseness dim-wittedness dimness doltishness dull-wittedness dullardism dullness dumbness duncery durability durity firmness flintiness grossness hardness hardness of heart hebetude impenetrability induration lethargy loutishness lumpishness mass materiality ninnyism oafdom oafishness obduracy obtuseness opacity palpability ponderability resistance restiveness simpletonianism slowness sluggishness solidity sottishness soundness stability steadiness steeliness stolidity stoniness stoutness strength stupidity sturdiness substance substantiality substantialness tangibility thick-headedness thick-wittedness toughness unteachability wrongheadedness yokelism