ineffectual

Adjective

• lacking in power or forcefulness
  • an ineffectual ruler
    
  • like an unable phoenix in hot ashes
    

• producing no result or effect
  • a futile effort
    
  • the therapy was ineffectual
    
  • an otiose undertaking
    
  • an unavailing attempt
    

• not producing an intended effect
  • an ineffective teacher
    
  • ineffective legislation
    

Related words

• Synonyms: 
  ineffective , unable , futile , otiose , unavailing , uneffective
• Antonyms: 
  effective , effectual , efficacious