Heard it through the grapevine
通過傳聞或非正式渠道得知消息，并非官方來源。
談論八卦或未經證實的消息時。
英文釋義
You learned something through means of a rumor.
例句
I heard it through the grapevine that they're getting married.
典故來源
源自19世紀美國電報線比喻，葡萄藤狀線路傳遞信息，后指流言傳播。