toughened

Adjective

• made hard or flexible or resilient especially by heat treatment
  • a sword of tempered steel
    
  • tempered glass
    

• physically toughened
  • the tough bottoms of his feet
    

Related words

• Synonyms: 
  tempered , treated , hardened , tough
• Antonyms: 
  untempered , unhardened , tender , untoughened