We found 40 dictionaries that define the word maniac:

General (27 matching dictionaries)

1. maniac: Longman Dictionary of Contemporary English
2. maniac: Merriam-Webster
3. -maniac, maniac: Oxford Learner's Dictionaries
4. maniac: American Heritage Dictionary of the English Language
5. -maniac, maniac: Collins English Dictionary
6. maniac: Vocabulary.com
7. Maniac, maniac: Wordnik
8. maniac: Cambridge Advanced Learner's Dictionary
9. -maniac, maniac: Wiktionary
10. -maniac, maniac: Webster's New World College Dictionary, 4th Ed.
11. maniac: The Wordsmyth English Dictionary-Thesaurus
12. maniac: Infoplease Dictionary
13. maniac: Dictionary.com
14. maniac (adj.): Online Etymology Dictionary
15. maniac: Cambridge Essential American English Dictionary
16. MANIAC, Maniac (Conan Gray song), Maniac (Girlicious song), Maniac (Michael Sembello song), Maniac (Norwegian TV series), Maniac (TV series), Maniac (band), Maniac (film), Maniac (miniseries), Maniac (producer), Maniac (single), Maniac (song), Maniac (truck), Maniac: Wikipedia, the Free Encyclopedia
17. Maniac: Online Plain Text English Dictionary
18. maniac: Webster's Revised Unabridged, 1913 Edition
19. maniac: Rhymezone
20. maniac: AllWords.com Multi-Lingual Dictionary
21. maniac: Webster's 1828 Dictionary
22. MANIAC: Stammtisch Beau Fleuve Acronyms
23. maniac: FreeDictionary.org
24. maniac: Mnemonic Dictionary
25. maniac: TheFreeDictionary.com

Art (1 matching dictionary)

26. -maniac: A Cross Reference of Latin and Greek Elements

Business (1 matching dictionary)

27. maniac: Legal dictionary

Computing (2 matching dictionaries)

28. MANIAC: CCI Computer
29. -maniac, maniac: Encyclopedia

Medicine (3 matching dictionaries)

30. maniac: Merriam-Webster Medical Dictionary
31. online medical dictionary (No longer online)
32. -maniac, maniac: Medical dictionary

Miscellaneous (1 matching dictionary)

33. MANIAC: Acronym Finder

Slang (2 matching dictionaries)

34. Maniac: Green’s Dictionary of Slang
35. maniac: Urban Dictionary

Sports (3 matching dictionaries)

36. Maniac: Dan's Poker
37. Texas Hold'em Dictionary (No longer online)
38. Maniac: Poker Terms

(Note: See maniacing as well.)

Definitions from Wiktionary ( ) ▸ noun:  An insane person, especially one who suffers from a mania. ▸ noun:  (figurative) A fanatic, a person with an obsession. ▸ noun:  (Philippines) Short for sex maniac. Similar: madman, maniacal, insane, lunatic, maniack, manic-depressive, mad man, morphiomaniac, mental patient, morphomaniac, more... Opposite: sane, rational, composed, level-headed Types: serial killer, mass murderer, spree killer, terrorist, stalker, pyromaniac, sadist, more... Phrases: sex maniac, 2nd World Tour Maniac, Maniac Mansion, Maniac Cop, Johnny the Homicidal Maniac, more... Adjectives: homicidal, poor, religious, dangerous, sexual, old, furious, crazed, suicidal, wretched, violent Colors:     red,     black,     neon green,     electric blue,     blood orange, more... ▸ Word origin ▸ Words similar to maniac ▸ Usage examples for maniac ▸ Idioms related to maniac ▸ Wikipedia articles (New!) ▸ Popular adjectives describing maniac ▸ Words that often appear near maniac ▸ Rhymes of maniac ▸ Invented words related to maniac