unable

American  

[uhn-ey-buhl] / ʌnˈeɪ bəl /

adjective

1. lacking the necessary power, competence, etc., to accomplish some specified act.

   He was unable to swim.

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unable British  

/ ʌnˈeɪbəl /

adjective

1. lacking the necessary power, ability, or authority (to do something); not able

2. archaic incompetent

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Synonym Usage

See incapable.

Etymology

Origin of unable

First recorded in 1350–1400; Middle English; un- ¹ + able

Explanation

If you're unable to do something, you just can't do it. This isn't necessarily a bad thing! You may be unable to tell a lie, no matter how much you want to blame your brother for breaking that window. When we're unable, we're incapable. If you're unable to speak French, but you speak German fluently, you might choose to spend the summer in Berlin rather than Quebec City. And when your neighbor is unable to walk her dog during the day, you could volunteer to walk it after school. Being unable is either "lacking ability," or "lacking power."

Example Sentences

Unable to get her to go places that I would enjoy as much as her, I started going by myself.

From Salon • Jun. 1, 2026

Unable to slow Saracens' quick ball, they conceded a fourth try to Carre, the prop powering over after a well worked line-out move.

From BBC • Apr. 19, 2026

Unable to ship petroleum and liquefied natural gas it had bought from the region, Vitol had to find replacements to send to customers.

From The Wall Street Journal • Apr. 12, 2026

Unable to run tours into North Korea, he has been offering trips through border areas so customers can catch glimpses into the secretive state from a distance.

From Barron's • Mar. 29, 2026

Unable to diagnose himself, in severe pain, and unable to continue with his work, he presented himself to Dr. Antonia Bagshawe, a physician at Nairobi Hospital.

From "The Hot Zone" by Richard Preston

Related Words

• helpless
• impotent
• inadequate
• incapable
• not able
• powerless
• sidelined
• unfit
• weak