soundness (n.)

• admissibility
• advantageousness
• agreeableness
• aplomb
• auspiciousness
• authenticity
• authority
• balance
• benevolence
• benignity
• body
• class
• cogency
• completeness
• concreteness
• constancy
• cool
• coolness
• density
• dependability
• desert
• durability
• entireness
• equilibrium
• excellence
• expedience
• fairness
• fastness
• favorableness
• fineness
• firmness
• force
• fullness
• goodness
• grace
• haleness
• hardness
• healthfulness
• healthiness
• helpfulness
• homeostasis
• imperturbability
• intactness
• integrity
• invariability
• invincibility
• justness
• kindness
• logic
• logicality
• logicalness
• lucidity
• marbles
• mass
• materiality
• merit
• mind
• nerve
• niceness
• normalcy
• normality
• orthodoxy
• palpability
• plausibility
• pleasantness
• plenitude
• practicality
• predictability
• profitableness
• quality
• rationality
• reason
• reasonableness
• reliability
• rightness
• saneness
• sang-froid
• sanity
• secureness
• security
• sense
• senses
• sensibleness
• skillfulness
• soberness
• sobriety
• solidity
• solvency
• stability
• stableness
• staunchness
• steadfastness
• steadiness
• stoutness
• strength
• sturdiness
• substance
• substantiality
• substantialness
• superiority
• tangibility
• temper
• toughness
• traditionalism
• trustworthiness
• uniformity
• usefulness
• validity
• value
• virtue
• virtuousness
• weight
• wholeness
• wholesomeness
• wit
• worth