run (one's) mouth(redirected from running their mouth)
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run (one's) mouth
To talk profusely, especially in an antagonizing way. Don't worry about him. He likes to run his mouth, but he won't do anything. If she keeps running her mouth at the referee, she's going to be ejected from this game. Every time I go down to the warehouse, Lonnie is there running his mouth. I don't know how the other guys can stand to hear him talking all day.