We found 29 dictionaries that define the word challenging:

General (23 matching dictionaries)

1. challenging: Merriam-Webster
2. challenging: Oxford Learner's Dictionaries
3. challenging: American Heritage Dictionary of the English Language
4. challenging: Collins English Dictionary
5. challenging: Vocabulary.com
6. Challenging, challenging: Wordnik
7. challenging: Cambridge Advanced Learner's Dictionary
8. challenging: Wiktionary
9. challenging: The Wordsmyth English Dictionary-Thesaurus
10. challenging: Infoplease Dictionary
11. challenging: Dictionary.com
12. challenging: Cambridge Essential American English Dictionary
13. Challenging: Wikipedia, the Free Encyclopedia
14. Challenging: Online Plain Text English Dictionary
15. challenging: Rhymezone
16. Challenging: AllWords.com Multi-Lingual Dictionary
17. challenging: Webster's 1828 Dictionary
18. challenging: FreeDictionary.org
19. challenging: Mnemonic Dictionary
20. challenging: TheFreeDictionary.com
21. challenging: Longman Dictionary of Contemporary English

Business (2 matching dictionaries)

22. challenging: Merriam-Webster Legal Dictionary
23. challenging: Legal dictionary

Computing (1 matching dictionary)

24. challenging: Encyclopedia

Medicine (2 matching dictionaries)

25. challenging: Merriam-Webster Medical Dictionary
26. challenging: Medical dictionary

Miscellaneous (1 matching dictionary)

27. challenging: Idioms

(Note: See challenge as well.)

Definitions from Wiktionary ( ) ▸ adjective:  Difficult, hard to do. ▸ noun:  The act of making a challenge. Similar: difficult, provocative, intriguing, thought-provoking, ambitious, stimulating, hard, tough, tricky, daunting, more... Opposite: simple, easy, effortless, straightforward, undemanding Types: difficult, arduous, formidable, strenuous, taxing, tough, more... Phrases: Challenging behaviour, challenging times, challenging exam, very challenging, physically challenging, more... Colors:     charcoal,     crimson,     indigo,     olive,     maroon, more... ▸ Words similar to challenging ▸ Usage examples for challenging ▸ Idioms related to challenging ▸ Wikipedia articles (New!) ▸ Popular adjectives describing challenging ▸ Popular nouns described by challenging ▸ Words that often appear near challenging ▸ Rhymes of challenging ▸ Invented words related to challenging