toughness (n.)

• abstruseness
• adhesiveness
• arduousness
• astringency
• austerity
• authoritarianism
• backbone
• body
• bottom
• bullheadedness
• burdensomeness
• callosity
• callousness
• chutzpah
• clamminess
• clotting
• coagulation
• cohesiveness
• complexity
• complication
• concreteness
• consistency
• courage
• curdling
• decisiveness
• density
• difficultness
• difficulty
• discipline
• durability
• endurance
• energy
• firmness
• force
• fortitude
• gameness
• gelatinousness
• gluiness
• glutinosity
• glutinousness
• grimness
• grit
• gumminess
• guts
• gutsiness
• hairiness
• hardiness
• hardness
• harshness
• heart
• heartiness
• heaviness
• immovability
• immutability
• impenetrability
• induration
• inelasticity
• inexorability
• inflexibility
• inspissation
• intransigence
• intransigency
• intricacy
• laboriousness
• lustiness
• mass
• materiality
• meticulousness
• mettle
• mettlesomeness
• might
• mightiness
• moxie
• nerve
• obduracy
• obstinacy
• onerousness
• oppressiveness
• palpability
• persistence
• persistency
• pith
• pluck
• pluckiness
• potency
• power
• powerfulness
• regimentation
• relentlessness
• resistance
• restiveness
• retention
• rigidity
• rigor
• rigorousness
• robustness
• ropiness
• ruggedness
• severity
• sliminess
• snugness
• solidity
• soundness
• spirit
• spunk
• stability
• stalwartness
• stamina
• steadiness
• sternness
• stickiness
• stiffness
• stodginess
• stoutness
• strength
• strenuousness
• strictness
• stringency
• stubbornness
• sturdiness
• substance
• substantiality
• substantialness
• tackiness
• tangibility
• tenaciousness
• tenacity
• thickening
• thickness
• tightness
• toilsomeness
• troublesomeness
• unalterability
• unchangeability
• unyieldingness
• vigor
• viscidity
• viscosity
• viscousness
• vitality