crazy; insane; mad.
affected with dementia.

Nearby words

  1. demeaning,
  2. demeanor,
  3. demeanour,
  4. demeclocycline,
  5. dement,
  6. dementedly,
  7. dementia,
  8. dementia praecox,
  9. dementia pugilistica,
  10. demento

Origin of demented

First recorded in 1635–45; dement + -ed2

Related formsde·ment·ed·ly, adverbde·ment·ed·ness, nounhalf-de·ment·ed, adjectivesem·i·de·ment·ed, adjective



verb (used with object) Obsolete.

to make mad or insane.

Origin of dement

1535–45; < Late Latin dēmentāre to deprive of mind, equivalent to Latin dēment- (stem of dēmēns) out of one's mind (dē- de- + ment- (stem of mēns) mind) + -āre infinitive suffix Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for demented

British Dictionary definitions for demented



mad; insane
Derived Formsdementedly, adverbdementedness, noun



(intr) to deteriorate mentally, esp because of old age
(tr) rare to drive mad; make insane

Word Origin for dement

C16: from Late Latin dēmentāre to drive mad, from Latin de- + mēns mind

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for demented
Online Etymology Dictionary, © 2010 Douglas Harper

Medicine definitions for demented




Mentally ill; insane.
Suffering from dementia.

The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.