Definition
To talk excessively in a loud and unrestrained manner; to speak without thinking or consideration.
信口开河
He always likes to shoot his mouth off about other people's ideas during meetings.
他总喜欢在会议上对别人的想法大放厥词。
Don't go shooting your mouth off to the media, you'll get yourself into trouble.
不要对媒体乱说话，你会给自己惹麻烦的。
She has a habit of shooting her mouth off before she even understands the situation.
她有个习惯，在还没了解情况之前就乱说话。