◎ 家贼难防 jiāzéi-nánfáng[thief in the family is difficult to detect; a thief from within is hard to guard against;it is difficult to forestall a thief within the house] 家属或内部的人作弊营私难以防范 -----------------国语辞典:比喻内部的敌人或坏人最难防范。《五灯会元.卷一四.同安志禅师法嗣》:「问:『家贼难防时如何?』师曰:『识得不为冤。』」
◎ 家贫如洗 jiāpín-rúxǐ[be in extreme poverty;as poor as a church mouse;as poor as job] 家中非常贫穷,如被水冲洗过一样,什么也没有 -----------------国语辞典:家里穷得像水洗过,一无所有。形容家境极为贫穷。元.秦?夫《剪发待宾.第一折》:「小生幼习儒业,颇读诗书,争奈家贫如洗。」《聊斋志异.卷一一.任秀》:「任子秀,时年十七,方从师读,由此废学,欲往寻父柩。母怜其幼,秀哀涕欲死,遂典赀治任,俾老仆佐之行,半年始还。殡后,家贫如洗。」
国语辞典:家境不如往昔富贵。《儒林外史.第一四回》:「而今也家道中落,那里一时拿的许多银子出来?」《文明小史.第五八回》:「自从家道中落之后,经过磨折,知道世界上尚有这等的境界,一心一意,想把已去的恢复过来。」英语 to come down in the world (idiom), to suffer a reversal of fortune