unable
Americanadjective
adjective
-
lacking the necessary power, ability, or authority (to do something); not able
-
archaic incompetent
Synonym Usage
See incapable.
Etymology
Origin of unable
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
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
But although the landing of Beagle 2 was successful, it was branded as a failed mission as it was unable to connect back to Earth once it landed.
From BBC ● Oct. 5, 2026
“Hi, I’m the Walmart AI agent. I see we were unable to process your refund. Are you calling about that?”
From The Wall Street Journal ● Oct. 4, 2026
According to the Associated Press, 19 states say that an intoxicated person is only considered incapacitated — and therefore unable to consent — if they were given drugs or alcohol without knowing.
From Salon ● Oct. 3, 2026
An attorney representing him has not yet been listed in available court documents, and The Times was unable to reach Lui for comment.
From Los Angeles Times ● Oct. 2, 2026
He had left the shelter around noon, unable to take the stress of simply waiting alone.
From "Mountain of Fire" by Rebecca E. F. Barone
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
