my foot idiom informal old-fashioned
（表示不相信对方所说的话）算了吧
used to mean that you do not believe what another person has just told you
"He says his car isn't working." "Not working my foot. He's just too lazy to come." “他说他的车坏了。”“鬼才相信他的话。他不过是太懒了，不想来。”