We found 12 dictionaries that define the word grumpiest:

General (10 matching dictionaries)

1. grumpiest: Merriam-Webster
2. grumpiest: Oxford Learner's Dictionaries
3. grumpiest: Collins English Dictionary
4. grumpiest: Vocabulary.com
5. Grumpiest, grumpiest: Wordnik
6. grumpiest: Cambridge Advanced Learner's Dictionary
7. grumpiest: Wiktionary
8. grumpiest: Dictionary.com
9. grumpiest: Cambridge Essential American English Dictionary
10. grumpiest: TheFreeDictionary.com

Business (1 matching dictionary)

11. grumpiest: Legal dictionary

Slang (1 matching dictionary)

12. Grumpiest: Urban Dictionary

(Note: See grumpy as well.)

Definitions from Wiktionary (grumpy) ▸ adjective:  Dissatisfied and irritable. ▸ noun:  (informal) A dissatisfied and irritable person. ▸ Also see grumpy Types: surly, ill-tempered, grouchy, cranky, irritable, bad-tempered, more... ▸ Words similar to grumpiest ▸ Usage examples for grumpiest ▸ Idioms related to grumpiest ▸ Wikipedia articles (New!) ▸ Popular adjectives describing grumpiest ▸ Popular nouns described by grumpiest ▸ Words that often appear near grumpiest ▸ Rhymes of grumpiest ▸ Invented words related to grumpiest