We found 17 dictionaries that define the word megalomaniacal:

General (13 matching dictionaries)

1. megalomaniacal: Merriam-Webster
2. megalomaniacal: Oxford Learner's Dictionaries
3. megalomaniacal: Collins English Dictionary
4. megalomaniacal: Vocabulary.com
5. megalomaniacal: Wordnik
6. megalomaniacal: Cambridge Advanced Learner's Dictionary
7. megalomaniacal: Wiktionary
8. megalomaniacal: Dictionary.com
9. Megalomaniacal: Wikipedia, the Free Encyclopedia
10. megalomaniacal: Rhymezone
11. megalomaniacal: FreeDictionary.org
12. megalomaniacal: Mnemonic Dictionary
13. megalomaniacal: TheFreeDictionary.com

Computing (1 matching dictionary)

14. megalomaniacal: Encyclopedia

Medicine (2 matching dictionaries)

15. megalomaniacal: Merriam-Webster Medical Dictionary
16. megalomaniacal: Medical dictionary

Slang (1 matching dictionary)

17. megalomaniacal: Urban Dictionary

(Note: See megalomania as well.)

Definitions from Wiktionary (megalomaniacal) ▸ adjective:  Megalomaniac. Similar: psychoneurotic, neurotic, logomaniacal, megaloud, insaniac, maniacal, fanatic, manicky, manic, mad-dog, more... Opposite: humble, unassuming, self-effacing ▸ Words similar to megalomaniacal ▸ Usage examples for megalomaniacal ▸ Idioms related to megalomaniacal ▸ Wikipedia articles (New!) ▸ Popular nouns described by megalomaniacal ▸ Words that often appear near megalomaniacal ▸ Rhymes of megalomaniacal ▸ Invented words related to megalomaniacal