Definition as Adjective

• (usually followed by `to') not having the necessary means or skill or know-how
• (usually followed by `to') lacking necessary physical or mental ability
• lacking in power or forcefulness

• ineffective, ineffectual

• "unable to get to town without a car"; "unable to obtain funds"

• "dyslexics are unable to learn to read adequately"; "the sun was unable to melt enough snow"

• "an ineffectual ruler"; "like an unable phoenix in hot ashes"

• Unable vs ineffective
• Unable vs ineffectual