big mouth noun
plural ∼ mouths [count] informal : a person who cannot keep a secret or who talks too much
▪ She's a big mouth. — used in phrases that describe a person who talks too much ▪ Why did you have to open your big mouth and tell everyone our business? ▪ Be careful of what you say around her—she has a big mouth. [=she is likely to tell other people what you said]
▪ She's a big mouth. — used in phrases that describe a person who talks too much ▪ Why did you have to open your big mouth and tell everyone our business? ▪ Be careful of what you say around her—she has a big mouth. [=she is likely to tell other people what you said]
— big–mouthed adjective
▪ The surprise was spoiled by my big-mouthed friend.
▪ The surprise was spoiled by my big-mouthed friend.
