- not able; lacking the ability, means, or power to do something
- helpless; feeble
This airplane is unable to fly.
The definition of unable is a person or thing that doesn't have the ability, power or authority to do something.
An example of unable is someone not being qualified to fly a plane.
- Lacking the necessary power, authority, or means; not able; incapable: unable to get to town without a car.
- Lacking mental or physical capability or efficiency; incompetent: unable to walk.
- Usage Problem Not susceptible to action or treatment: a project unable to be financed with government funds. See Usage Note at able.
un- +"Ž able
- She fluffed the pillow and changed position, unable to sleep.
- We both looked at her intently, unable to respond.
- She clung to him, unable to trust her voice or thoughts.
- "I'm pretty sure he gets the picture," Damian said, unable to help his amusement.
- She was unable to pin him down on the cases of ours she'd documented earlier but he practically admitted he was personally responsible for all them and more.