smell是聞的意思，rat指老鼠。這個諺語跟貓有關，據說貓即使是在看不見老鼠的狀態下，也可以聞出躲藏在暗處的老鼠，而如果是人說I smell a rat，就是指雖然沒有直接的證據或跡象顯示出哪裡有問題，但憑著自己的直覺，覺得有可疑的地方，現在一起來看看下面例句與相關的用法吧！

例：I smell a rat! Something’s not right with his story.
( 我覺得有鬼！他的說法一定有哪裡不對勁。)
例：I smelt a rat when Noah offered to sell me the car at such a low price. That’s why I turned down his offer on the spot. It’s a good thing that I made the decision because the car turned out to be stolen.
( Noah 說要用很低的價錢賣車給我時，我覺得事有蹊蹺，所以當場拒絕了他的提議。幸好我作了這樣的決定，因為這部車原來是部贓車。)

另外fishy這個字也可以形容讓人起疑的人事物，也就是suspicious的意思，再來看看兩個例句吧！
例：It seems fishy that all the services here are free of charge.
( 這裡的所有服務項目都免費，似乎有些可疑。)
例：The police became suspicious when they found out that he had lied about his whereabouts.

( 警方發現他對自己的去處撒了謊時，他們起了疑心。)

圖片來源：http://pdpics.com/photo/5536-smell-a-rat-phrase/