functioning

Adjective

• performing or able to perform its regular function
  • a functioning flashlight
    

Noun

• process or manner of functioning or operating
  • the power of its engine determines its operation
    
  • the plane's operation in high winds
    
  • they compared the cooking performance of each oven
    
  • the jet's performance conformed to high standards
    

Related words

• Synonyms: 
  operation , performance
• Antonyms: 
  malfunctioning , nonfunctional