demented
Americanadjective
-
crazy; insane; mad.
- Synonyms:
- unbalanced, deranged, crazed, lunatic
-
affected with dementia.
adjective
Other Word Forms
- dementedly adverb
- dementedness noun
- half-demented adjective
- semidemented adjective
Etymology
Origin of demented
Explanation
Demented is an adjective describing behavior that is crazy, unhinged, or insane. Someone is demented when they have gone off the deep end. Demented literally means "suffering from dementia," although in current culture it is used quite often to tease a sibling or good friend: "My brother thinks I am demented because I like to eat peanut butter and salami sandwiches."
Vocabulary lists containing demented
Speak
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The Pigman
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"Roller Girl" by Victoria Jamieson
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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.
It’s positively demented, but it’s not insanity for insanity’s sake.
From Salon • Apr. 5, 2026
During his early career, Shepard savaged Vietnam-era conservatism, preferring the hippie vibe of the Bay Area to what he called the “sprawling, demented snake of L.A. to the south.”
From Los Angeles Times • Nov. 4, 2025
Sam Neill stars in “Madness” as an insurance investigator who, sent to find a missing, bestselling horror author, ends up stumbling into the demented New England small town of the author’s books.
From The Wall Street Journal • Oct. 29, 2025
It’s just another weekly edition of “SmackDown” in Don’s demented mind.
From Salon • Aug. 1, 2025
There isn’t enough coal to cook the dinner, the water isn’t boiling anymore and she says she’s demented with worry.
From "Angela's Ashes: A Memoir" by Frank McCourt
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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.