demented

Etymology

It is formed from English dement + -ed, from the now archaic verb dement, to drive mad.^{[2][3][4][5][6]} The verb, recorded from 1545, is from Late Latin dēmentō (“to deceive; to be mad; to drive mad”),^[2][3][7] probably through Middle French démenter,^[3][4] from Latin dēmēns (“out of one's mind, insane”),^[2][4] from the phrase dē (“out of, away from”) mente (“mind”), with the ablative of mēns (“mind”).^[3][4] An earlier English adjective dement, from Middle French dement and Latin dēmēns, is recorded from before 1500.^[2]

Earliest recorded meaning

Mentally unbalanced, behaving irrationally, beside oneself: 1632, in Francis Quarles's Divine Fancies.^[2][8] Barnhart and Dictionary.com put it about a decade later (1644; 1635–45),^[3][9] and Etymonline in the 1640s.^[4]

Semantic evolution

The word began with people driven out of their minds, often by strong emotion, and could also be used more loosely of someone wildly excited or infatuated.^[2] From 1726, in Defoe, it described behaviour or ideas that showed such a state;^[2] since 1854 it has also been used of wild or grotesque things.^[2] The medical sense, affected with dementia, dates from 1830,^[2] and the Shorter Oxford places it in the late 19th century.^[5] Collins now labels this sense offensive.^[10] In Caithness dialect demented meant stupid or nonsensical.^[11]

Timeline

• 1545 – the verb dement, to drive mad.^[2][3]
• 1632 – out of one's mind; beside oneself with emotion.^[2][8]
• 1726 – of behaviour or utterances, showing such a state.^[2]
• 1830 – in medicine, affected with dementia.^[2]
• 1854 – of things, wild or grotesque in movement or appearance.^[2]

Meanings

Adjective

1. Behaving wildly or irrationally, as if mad; beside oneself with worry, anger or excitement: The children were demented with boredom by the third day of rain.^[10][2][8]
2. (medicine) Affected with dementia; of unsound mind.^[8][2][10]
3. Showing or caused by such a state: demented laughter.^[8][2]

Word family

• dementedly
• dementedness
• semidemented

Related words

• dementia
• mental
• mind

References

1. ^ Wiktionary, the free dictionary, https://en.wiktionary.org
2. ^ a b c d e f g h i j k l m n o p q Oxford English Dictionary Online (accessed March 2026), Oxford: Oxford University Press
3. ^ a b c d e f Barnhart, Robert K. (1988), The Barnhart Dictionary of Etymology
4. ^ a b c d e Harper, Douglas. Online Etymology Dictionary, https://www.etymonline.com
5. ^ a b Shorter Oxford English Dictionary on Historical Principles (2002), 5th ed., ed. William R. Trumble and Angus Stevenson, Oxford: Oxford University Press
6. ^ Stevenson, Angus, ed. (2010), Oxford Dictionary of English, 3rd ed., Oxford: Oxford University Press
7. ^ Hoad, T. F., ed. (1986), The Concise Oxford Dictionary of English Etymology, Oxford: Clarendon Press
8. ^ a b c d e Merriam-Webster Unabridged Dictionary (2024), online ed., Springfield, Mass.: Merriam-Webster
9. ^ Dictionary.com Unabridged (2016), based on the Random House Unabridged Dictionary, New York: Random House
10. ^ a b c Collins English Dictionary (2023), Glasgow: HarperCollins
11. ^ Wright, Joseph, ed. (1898–1905), The English Dialect Dictionary, 6 vols., Oxford: Henry Frowde; via EDD Online 4.0, University of Innsbruck (CC BY 4.0)