(n.) The quality or state of being tough.

Spartanism abstruseness adamantness adhesiveness arduousness astringency austerity authoritarianism backbone body bothersomeness bottom bullheadedness burdensomeness callosity callousness chutzpah clabbering clamminess clotting coagulation cohesiveness colloidality complexity complication concreteness consistency courage curdling decisiveness demandingness density difficultness difficulty discipline doughiness dourness durability durity endurance energy exactingness firmness flintiness force fortitude gameness gelatinity gelatinousness gluelikeness gluiness glutinosity glutinousness grimness grit gumlikeness gumminess guts gutsiness guttiness hairiness hard-bittenness hard-nosedness hardiness hardness hardness of heart harshness heart heart of oak heartiness heaviness immovability immutability impenetrability implacability impliability incrassation induration inelasticity inexorability inflexibility inspissation intestinal fortitude intransigeance intransigence intransigency intransigentism intricacy irreconcilability jellification jellylikeness laboriousness lentor lustihood lustiness mass materiality meticulousness mettle mettlesomeness might mightiness moxie mucilaginousness nerve obduracy obstinacy onerousness oppressiveness palpability pastiness persistence persistency pith pluck pluckiness ponderability potency power powerfulness regimentation relentlessness resistance restiveness retention rigid discipline rigidity rigor rigorism rigorousness robustness ropiness ruggedness severity slabbiness sliminess snugness solidity soundness spirit spissitude spunk spunkiness stability stalwartness stamina staying power steadiness steeliness sternness stick-to-itiveness stickiness sticking power stiff temper stiffness stodginess stoniness stout heart stoutness strength strength of will strenuousness strictness stringency stringiness stubbornness sturdiness substance substantiality substantialness syrupiness tackiness tangibility tenaciousness tenacity thickening thickness tightness toilsomeness treacliness troublesomeness true grit unalterability unbendingness unchangeability uncompromisingness ungivingness unrelentingness unyieldingness vigor vigorousness viscidity viscosity viscousness vitality