We found 32 dictionaries that define the word demented:

General (25 matching dictionaries)

1. demented: Merriam-Webster
2. demented: Oxford Learner's Dictionaries
3. demented: American Heritage Dictionary of the English Language
4. demented: Collins English Dictionary
5. demented: Vocabulary.com
6. Demented, demented: Wordnik
7. demented: Cambridge Advanced Learner's Dictionary
8. demented: Wiktionary
9. demented: Webster's New World College Dictionary, 4th Ed.
10. demented: The Wordsmyth English Dictionary-Thesaurus
11. demented: Infoplease Dictionary
12. demented: Dictionary.com
13. demented: Online Etymology Dictionary
14. demented: Cambridge Essential American English Dictionary
15. Demented (disambiguation): Wikipedia, the Free Encyclopedia
16. Demented: Online Plain Text English Dictionary
17. demented: Webster's Revised Unabridged, 1913 Edition
18. demented: Rhymezone
19. demented: AllWords.com Multi-Lingual Dictionary
20. demented: FreeDictionary.org
21. demented: Mnemonic Dictionary
22. demented: TheFreeDictionary.com
23. demented: Longman Dictionary of Contemporary English

Business (1 matching dictionary)

24. demented: Legal dictionary

Computing (2 matching dictionaries)

25. demented: Free On-line Dictionary of Computing
26. demented: Encyclopedia

Medicine (3 matching dictionaries)

27. demented: Merriam-Webster Medical Dictionary
28. online medical dictionary (No longer online)
29. demented: Medical dictionary

Slang (1 matching dictionary)

30. Demented: Urban Dictionary

(Note: See dementedly as well.)

Definitions from Wiktionary ( ) ▸ adjective:  Insane; mentally ill. ▸ adjective:  Having dementia. ▸ adjective:  (informal) Crazy; ridiculous. Similar: brainsick, insane, distracted, mad, crazy, sick, unhinged, unbalanced, disturbed, chemically imbalanced, more... Opposite: sane, lucid, rational, coherent, clear-headed Types: insane, insanely, insanest, more... Phrases: Cecil B. Demented, Demented Are Go, For the Demented, opposite of demented, deranged demented, more... Colors:     black,     blood red,     dark purple,     sickly green,     midnight blue, more... ▸ Word origin ▸ Words similar to demented ▸ Usage examples for demented ▸ Idioms related to demented ▸ Wikipedia articles (New!) ▸ Popular nouns described by demented ▸ Words that often appear near demented ▸ Rhymes of demented ▸ Invented words related to demented