changeless

Adjective

• remaining the same for indefinitely long times

• unvarying in nature
  • maintained a constant temperature
    
  • principles of unvarying validity
    

• not subject or susceptible to change or variation in form or quality or nature
  • the view of that time was that all species were immutable, created by God
    

Related words

• Synonyms: 
  unalterable , constant , invariant , unvarying , immutable
• Antonyms: 
  mutable , changeable