We found 3 dictionaries that define the word open one's mouth:

General (3 matching dictionaries)

1. open one's mouth: Merriam-Webster
2. open one's mouth: Oxford Learner's Dictionaries
3. open one's mouth: Wiktionary

Definitions from Wiktionary (open one's mouth) ▸ verb:  (idiomatic) to speak ▸ Words similar to open one's mouth ▸ Usage examples for open one's mouth ▸ Idioms related to open one's mouth ▸ Wikipedia articles (New!) ▸ Words that often appear near open one's mouth ▸ Rhymes of open one's mouth ▸ Invented words related to open one's mouth