Tā xìnkǒu-kāihé, chéngnuò le hěnduō zuò bùdào de shì.
He spoke irresponsibly and promised many things he couldn't deliver.
Tips
memory
Picture a mouth (口) opened wide like a river (河), with words flooding out uncontrolled. 信口 means 'whatever comes from the mouth,' and 开河 means 'opening a river channel.' Words flow as freely and unthinkingly as water.
