WordRel.com

• the quality or attribute of being firm and steadfast

  synonym	stableness
  antonym	instability
  derivation	stable
  hypernym	firmnesssteadiness

• the quality of being enduring and free from change or variation

  synonym	constancy
  derivation	stablestable
  attribute	constantinconstant
  hypernym	changelessnessunchangeabilityunchangeablenessunchangingness
  hyponym	invariancemetastabilitymonotony

• a stable order (especially of society)

  antonym	instability
  hypernym	order