We found 7 dictionaries that define the word run one's mouth:

General (3 matching dictionaries)

1. run one's mouth: Merriam-Webster
2. run one's mouth: Wiktionary
3. run one's mouth: TheFreeDictionary.com

Business (2 matching dictionaries)

4. run one's mouth: Legal dictionary
5. run one's mouth: Financial dictionary

Computing (1 matching dictionary)

6. run one's mouth: Encyclopedia

Miscellaneous (1 matching dictionary)

7. run one's mouth: Idioms

Definitions from Wiktionary (Run one's mouth) ▸ verb:  Alternative form of run off at the mouth [(idiomatic) To talk excessively.] ▸ Words similar to run one's mouth ▸ Usage examples for run one's mouth ▸ Idioms related to run one's mouth ▸ Wikipedia articles (New!) ▸ Words that often appear near run one's mouth ▸ Rhymes of run one's mouth ▸ Invented words related to run one's mouth