We found 32 dictionaries that define the word failing:

General (24 matching dictionaries)

1. failing: Merriam-Webster
2. failing, failing: Oxford Learner's Dictionaries
3. failing: American Heritage Dictionary of the English Language
4. failing: Collins English Dictionary
5. failing: Vocabulary.com
6. Failing, failing: Wordnik
7. failing: Cambridge Advanced Learner's Dictionary
8. Failing, failing: Wiktionary
9. failing: Webster's New World College Dictionary, 4th Ed.
10. failing: The Wordsmyth English Dictionary-Thesaurus
11. failing: Infoplease Dictionary
12. Failing, failing: Dictionary.com
13. failing: Cambridge Essential American English Dictionary
14. Failing: Online Plain Text English Dictionary
15. failing: Webster's Revised Unabridged, 1913 Edition
16. failing: Rhymezone
17. Failing: AllWords.com Multi-Lingual Dictionary
18. failing: Webster's 1828 Dictionary
19. failing: FreeDictionary.org
20. failing: Mnemonic Dictionary
21. failing: TheFreeDictionary.com
22. failing: Longman Dictionary of Contemporary English

Business (2 matching dictionaries)

23. failing: Legal dictionary
24. failing: Financial dictionary

Computing (1 matching dictionary)

25. failing: Encyclopedia

Medicine (1 matching dictionary)

26. failing: Merriam-Webster Medical Dictionary

Miscellaneous (2 matching dictionaries)

27. FAILING: Acronym Finder
28. failing: Idioms

Science (1 matching dictionary)

29. Bryological (No longer online)

Slang (1 matching dictionary)

30. failing: Urban Dictionary

(Note: See fail as well.)

Definitions from Wiktionary ( ) ▸ noun:  weakness; defect ▸ noun:  A surname. Similar: weakness, unsatisfactory, deteriorating, unsuccessful, declining, retrogressive, regressing, regressive, retrograde, failure, more... Opposite: succeeding, thriving, excelling, winning, prospering Types: flunking, failing out, flunk out, more... Phrases: failing that, never failing, These Systems Are Failing, failing to, failing to beat the bell, more... Adjectives: whom, never, family, palpable, sympathetic, greatest, horses, best Colors:     gray,     black,     brown,     dull red,     dark blue, more... ▸ Words similar to failing ▸ Usage examples for failing ▸ Idioms related to failing ▸ Wikipedia articles (New!) ▸ Popular adjectives describing failing ▸ Words that often appear near failing ▸ Rhymes of failing ▸ Invented words related to failing