We found 30 dictionaries that define the word flare up:

General (23 matching dictionaries)

1. flare-up: Merriam-Webster
2. flare-up, flare up: Oxford Learner's Dictionaries
3. flare-up: American Heritage Dictionary of the English Language
4. flare-up, flare-up: Collins English Dictionary
5. flare-up, flare up: Vocabulary.com
6. flare-up: Wordnik
7. flare-up, flare up: Cambridge Advanced Learner's Dictionary
8. flare-up, flare up: Wiktionary
9. flare-up: Webster's New World College Dictionary, 4th Ed.
10. flare-up: The Wordsmyth English Dictionary-Thesaurus
11. flare-up, flare up: Dictionary.com
12. Flare-up: Wikipedia, the Free Encyclopedia
13. Flare-up: Online Plain Text English Dictionary
14. flare-up: Webster's Revised Unabridged, 1913 Edition
15. flare-up, flare up: Rhymezone
16. Flare-up: AllWords.com Multi-Lingual Dictionary
17. Flare-up, Flare-up: Dictionary of Phrase and Fable (1898)
18. flare-up, flare up: FreeDictionary.org
19. flare-up, flare up: Mnemonic Dictionary
20. flare-up, flare up: TheFreeDictionary.com
21. flare up: Longman Dictionary of Contemporary English

Business (1 matching dictionary)

22. flare-up: Legal dictionary

Computing (1 matching dictionary)

23. flare-up, flare up: Encyclopedia

Medicine (3 matching dictionaries)

24. flare up: Sound Alike Words
25. flare-up: Medical dictionary
26. Inflammatory Bowel Disease Glossary (No longer online)

Miscellaneous (1 matching dictionary)

27. flare up: Idioms

Slang (1 matching dictionary)

28. flare up: Green’s Dictionary of Slang

(Note: See flare_ups as well.)

Definitions from Wiktionary (flare up) ▸ verb:  (intransitive) To burn brightly again. ▸ verb:  (intransitive) To become more intense suddenly. ▸ verb:  (intransitive, sometimes with “out” instead of “up”) To burst out suddenly, as in anger. Similar: erupt, burst out, flare, break open, blaze up, flame up, reflash, upflare, blaze, flame out, more... Types: exacerbation, relapse, worsening, reactivation, more... Phrases: to flare up, more... Adjectives: flush, combust, flash, aflare, overfire, kindle, fire, explosive, flame, overfired, flushy ▸ Words similar to flare up ▸ Usage examples for flare up ▸ Idioms related to flare up ▸ Wikipedia articles (New!) ▸ Words that often appear near flare up ▸ Rhymes of flare up ▸ Invented words related to flare up