We found 10 dictionaries that define the word testiest:

General (9 matching dictionaries)

1. testiest: Merriam-Webster
2. testiest: Collins English Dictionary
3. testiest: Vocabulary.com
4. testiest: Cambridge Advanced Learner's Dictionary
5. testiest: Wiktionary
6. testiest: Dictionary.com
7. testiest: Cambridge Essential American English Dictionary
8. testiest: FreeDictionary.org
9. testiest: TheFreeDictionary.com

Business (1 matching dictionary)

10. testiest: Legal dictionary

(Note: See testy as well.)

Definitions from Wiktionary (testy) ▸ adjective:  Easily annoyed, irritable. ▸ adjective:  Marked by impatience or ill humor. ▸ Also see testy Types: hardest, most difficult, simplest, easiest, more... ▸ Words similar to testiest ▸ Usage examples for testiest ▸ Idioms related to testiest ▸ Wikipedia articles (New!) ▸ Popular nouns described by testiest ▸ Words that often appear near testiest ▸ Rhymes of testiest ▸ Invented words related to testiest